MHT CET 2026 Chemistry Question Paper with Answer and Solution

806 QuestionsEnglishWith Solutions

ChemistryQ151–250 of 806 questions

Page 4 of 12 · English

151
ChemistryDifficultMCQMHT CET · 2026
Calculate the work done for the following reaction at $27^{\circ}C$: $C_2H_4(g) + H_2(g) \rightarrow C_2H_6(g)$ $(R = 8.314 \text{ J K}^{-1} \text{mol}^{-1})$ (in $\text{ J}$)
A
$2494.2$
B
$124.71$
C
$3741.3$
D
$187.07$

Solution

(A) The formula for work done in a chemical reaction is $W = -\Delta n_g RT$.
Step $1$: Calculate the change in the number of moles of gaseous species, $\Delta n_g = n_p - n_r$.
$\Delta n_g = 1 - (1 + 1) = 1 - 2 = -1 \text{ mol}$.
Step $2$: Convert temperature to Kelvin: $T = 27 + 273 = 300 \text{ K}$.
Step $3$: Substitute the values into the formula: $W = -(-1 \text{ mol}) \times (8.314 \text{ J K}^{-1} \text{mol}^{-1}) \times (300 \text{ K})$.
$W = 1 \times 8.314 \times 300 = 2494.2 \text{ J}$.
152
ChemistryDifficultMCQMHT CET · 2026
If $2 \text{ mole}$ of an ideal gas expand isothermally and reversibly at $27^{\circ}C$ from $1 \text{ dm}^3$ to $1 \text{ m}^3$, calculate the work done. [$R = 8.314 \text{ J K}^{-1} \text{mol}^{-1}$] (in $\text{ kJ}$)
A
$-49.95$
B
$-99.90$
C
$-34.46$
D
$-68.92$

Solution

(C) Step $1$: Identify the given values.
$n = 2 \text{ mol}$, $T = 27^{\circ}C = 300 \text{ K}$, $V_1 = 1 \text{ dm}^3 = 10^{-3} \text{ m}^3$, $V_2 = 1 \text{ m}^3$, $R = 8.314 \text{ J K}^{-1} \text{mol}^{-1}$.
Step $2$: Use the formula for isothermal reversible work: $W = -nRT \ln\left(\frac{V_2}{V_1}\right)$.
Step $3$: Substitute the values: $W = -2 \times 8.314 \times 300 \times \ln\left(\frac{1}{10^{-3}}\right)$.
Step $4$: Calculate the natural logarithm: $\ln(1000) \approx 6.9078$.
Step $5$: Calculate the final value: $W = -4988.4 \times 6.9078 \approx -34446 \text{ J} = -34.45 \text{ kJ}$.
The closest option is $-34.46 \text{ kJ}$.
153
ChemistryMediumMCQMHT CET · 2026
Which of the following processes exhibits a decrease in the internal energy of a system?
A
Isothermal expansion of an ideal gas.
B
Isothermal compression of an ideal gas.
C
Adiabatic expansion of an ideal gas.
D
Adiabatic compression of an ideal gas.

Solution

(C) For an ideal gas, the internal energy $U$ is a function of temperature $T$ only, i.e., $U = f(T)$.
$1$. In isothermal processes, $\Delta T = 0$, so $\Delta U = 0$.
$2$. In adiabatic processes, the first law of thermodynamics is $\Delta U = q + w$. Since $q = 0$, $\Delta U = w$.
$3$. For adiabatic expansion, the gas does work on the surroundings, so $w < 0$. Thus, $\Delta U < 0$, which means internal energy decreases.
$4$. For adiabatic compression, work is done on the gas, so $w > 0$. Thus, $\Delta U > 0$, which means internal energy increases.
Therefore, adiabatic expansion leads to a decrease in internal energy.
154
ChemistryDifficultMCQMHT CET · 2026
Calculate the change in internal energy $(\Delta U)$ if an ideal gas expands from $0.5 \text{ dm}^3$ to $3.5 \text{ dm}^3$ at a constant pressure of $2 \text{ bar}$ by absorbing $1800 \text{ J}$ of heat energy. (in $\text{ J}$)
A
$1200$
B
$600$
C
$1800$
D
$2400$

Solution

(A) Step $1$: Identify the given values.
Heat absorbed $(q)$ = $+1800 \text{ J}$ (positive as heat is absorbed).
Pressure $(P)$ = $2 \text{ bar} = 2 \times 10^5 \text{ Pa}$.
Initial volume $(V_1)$ = $0.5 \text{ dm}^3 = 0.5 \times 10^{-3} \text{ m}^3$.
Final volume $(V_2)$ = $3.5 \text{ dm}^3 = 3.5 \times 10^{-3} \text{ m}^3$.
Step $2$: Calculate the work done $(w)$.
$w = -P \Delta V = -P(V_2 - V_1)$.
$w = -2 \times 10^5 \text{ Pa} \times (3.5 - 0.5) \times 10^{-3} \text{ m}^3$.
$w = -2 \times 10^5 \times 3 \times 10^{-3} \text{ J} = -600 \text{ J}$.
Step $3$: Calculate the change in internal energy $(\Delta U)$ using the first law of thermodynamics.
$\Delta U = q + w$.
$\Delta U = 1800 \text{ J} + (-600 \text{ J}) = 1200 \text{ J}$.
155
ChemistryDifficultMCQMHT CET · 2026
Calculate the $pH$ of a buffer solution containing $0.1 \text{ M } CH_3COOH$ and $0.1 \text{ M } CH_3COONa$ $[K_a = 1.8 \times 10^{-5}]$.
A
$4.745$
B
$7.41$
C
$8.76$
D
$1.00$

Solution

(A) Using the Henderson-Hasselbalch equation: $pH = pK_a + \log \frac{[Salt]}{[Acid]}$.
First, calculate $pK_a$: $pK_a = -\log(K_a) = -\log(1.8 \times 10^{-5}) = 5 - \log(1.8) = 5 - 0.255 = 4.745$.
Since $[Salt] = [CH_3COONa] = 0.1 \text{ M}$ and $[Acid] = [CH_3COOH] = 0.1 \text{ M}$, the ratio $\frac{[Salt]}{[Acid]} = 1$.
Therefore, $pH = 4.745 + \log(1) = 4.745 + 0 = 4.745$.
156
ChemistryMediumMCQMHT CET · 2026
What happens when $CuSO_4$ is dissolved in water? Identify the correct statement from the following:
A
The anion of the salt reacts with water.
B
Its solution will turn red litmus into blue.
C
The $pH$ of the solution will be less than $7$.
D
The $CuSO_4$ will not undergo hydrolysis reaction.

Solution

(C) $1$. $CuSO_4$ is a salt of a strong acid $(H_2SO_4)$ and a weak base $(Cu(OH)_2)$.
$2$. In water, it dissociates into $Cu^{2+}$ and $SO_4^{2-}$ ions.
$3$. The $Cu^{2+}$ ion undergoes cationic hydrolysis: $Cu^{2+} + 2H_2O \rightleftharpoons Cu(OH)_2 + 2H^+$.
$4$. Due to the production of $H^+$ ions, the solution becomes acidic, resulting in a $pH < 7$.
157
ChemistryMediumMCQMHT CET · 2026
What happens when solid $Na_2CO_3$ is dissolved in water?
A
an increase in $[OH^-]$
B
no change in $pH$
C
an increase in $[H^+]$ ions
D
turns blue litmus red

Solution

(A) $Na_2CO_3$ is a salt of a strong base $(NaOH)$ and a weak acid $(H_2CO_3)$.
When dissolved in water, it undergoes anionic hydrolysis: $CO_3^{2-} + H_2O \rightleftharpoons HCO_3^- + OH^-$.
This reaction produces $OH^-$ ions, which increases the concentration of $[OH^-]$ and makes the solution basic $(pH > 7)$.
158
ChemistryMediumMCQMHT CET · 2026
Which of the following aqueous solutions of salts has $pH < 7$ at $298 \text{ K}$?
A
$KNO_3$
B
$Na_2CO_3$
C
$CH_3COONa$
D
$CuCl_2$

Solution

(D) $1$. $KNO_3$ is a salt of a strong acid $(HNO_3)$ and a strong base $(KOH)$, so its aqueous solution is neutral $(pH = 7)$.
$2$. $Na_2CO_3$ is a salt of a weak acid $(H_2CO_3)$ and a strong base $(NaOH)$, so its aqueous solution is basic $(pH > 7)$.
$3$. $CH_3COONa$ is a salt of a weak acid $(CH_3COOH)$ and a strong base $(NaOH)$, so its aqueous solution is basic $(pH > 7)$.
$4$. $CuCl_2$ is a salt of a strong acid $(HCl)$ and a weak base $(Cu(OH)_2)$. Due to the hydrolysis of the $Cu^{2+}$ ion, the solution becomes acidic $(pH < 7)$.
159
ChemistryMediumMCQMHT CET · 2026
Identify from the following salts an example of a salt of a strong acid and a weak base.
A
Ammonium acetate
B
Sodium acetate
C
Copper $(II)$ chloride
D
Sodium carbonate

Solution

(C) Step $1$: Identify the acid and base components for each salt.
Step $2$: $Ammonium \ acetate$ is formed from $CH_3COOH$ (weak acid) and $NH_4OH$ (weak base).
Step $3$: $Sodium \ acetate$ is formed from $CH_3COOH$ (weak acid) and $NaOH$ (strong base).
Step $4$: $Copper(II) \ chloride$ $(CuCl_2)$ is formed from $HCl$ (strong acid) and $Cu(OH)_2$ (weak base).
Step $5$: $Sodium \ carbonate$ is formed from $H_2CO_3$ (weak acid) and $NaOH$ (strong base).
Step $6$: Therefore, $CuCl_2$ is the correct example of a salt of a strong acid and a weak base.
160
ChemistryMediumMCQMHT CET · 2026
Which of the following salts undergoes anionic hydrolysis?
A
$CuSO_4$
B
$Na_2CO_3$
C
$NH_4Cl$
D
$FeCl_3$

Solution

(B) $1$. Anionic hydrolysis occurs when the anion of a salt reacts with water to form a basic solution.
$2$. This happens in salts formed from a weak acid and a strong base.
$3$. $Na_2CO_3$ is a salt of a weak acid $(H_2CO_3)$ and a strong base $(NaOH)$.
$4$. The anion $CO_3^{2-}$ reacts with water: $CO_3^{2-} + H_2O \rightleftharpoons HCO_3^- + OH^-$, resulting in anionic hydrolysis.
$5$. $CuSO_4$, $NH_4Cl$, and $FeCl_3$ are salts of strong acids and weak bases, which undergo cationic hydrolysis.
161
ChemistryMediumMCQMHT CET · 2026
Which of the following salts does not undergo hydrolysis?
A
Ammonium nitrate
B
Sodium acetate
C
Ammonium cyanide
D
Sodium nitrate

Solution

(D) Step $1$: Hydrolysis occurs when a salt is formed from a weak acid and a weak base, a weak acid and a strong base, or a strong acid and a weak base.
Step $2$: $NaNO_3$ is a salt formed from a strong acid $(HNO_3)$ and a strong base $(NaOH)$.
Step $3$: Salts of strong acids and strong bases do not undergo hydrolysis because their ions do not react with water to change the $pH$ of the solution.
Step $4$: Therefore, $NaNO_3$ does not undergo hydrolysis.
162
ChemistryMediumMCQMHT CET · 2026
Which of the following aqueous salt solutions has the least $pH$ value?
A
$Na_2CO_3$
B
$CuCl_2$
C
$CH_3COONa$
D
$NaNO_3$

Solution

(B) $(1)$ $Na_2CO_3$ is a salt of a strong base $(NaOH)$ and a weak acid $(H_2CO_3)$, so it is basic $(pH > 7)$.
$(2)$ $CuCl_2$ is a salt of a weak base $(Cu(OH)_2)$ and a strong acid $(HCl)$, so it is acidic $(pH < 7)$.
$(3)$ $CH_3COONa$ is a salt of a strong base $(NaOH)$ and a weak acid $(CH_3COOH)$, so it is basic $(pH > 7)$.
$(4)$ $NaNO_3$ is a salt of a strong base $(NaOH)$ and a strong acid $(HNO_3)$, so it is neutral $(pH = 7)$.
Therefore, $CuCl_2$ has the least $pH$ value.
163
ChemistryEasyMCQMHT CET · 2026
What is the normal pH of human blood?
A
0
B
9
C
4
D
1

Solution

The normal physiological pH of human blood is approximately 7.4.
164
ChemistryDifficultMCQMHT CET · 2026
$2.8 \text{ g}$ of $KOH$ is dissolved in a $500 \text{ mL}$ solution at $298 \text{ K}$. What is the $pH$ of the solution? (Molar mass of $KOH = 56 \text{ g/mol}$)
A
$1$
B
$8$
C
$11$
D
$13$

Solution

(D) Step $1$: Calculate the number of moles of $KOH$: $n = \frac{\text{mass}}{\text{molar mass}} = \frac{2.8 \text{ g}}{56 \text{ g/mol}} = 0.05 \text{ mol}$.
Step $2$: Calculate the molarity $(M)$ of the solution: $M = \frac{n}{V(\text{in L})} = \frac{0.05 \text{ mol}}{0.5 \text{ L}} = 0.1 \text{ M}$.
Step $3$: Since $KOH$ is a strong base, $[OH^-] = 0.1 \text{ M} = 10^{-1} \text{ M}$.
Step $4$: Calculate $pOH$: $pOH = -\log[OH^-] = -\log(10^{-1}) = 1$.
Step $5$: Calculate $pH$: $pH = 14 - pOH = 14 - 1 = 13$.
165
ChemistryDifficultMCQMHT CET · 2026
$A$ weak monobasic acid is $0.04 \%$ dissociated in $0.25 \text{ M}$ solution. What is the $pH$ of the solution?
A
$5$
B
$4$
C
$3$
D
$10$

Solution

(B) Step $1$: Calculate the concentration of $H^+$ ions.
$[H^+] = C \times \alpha$
Given $C = 0.25 \text{ M}$ and $\alpha = \frac{0.04}{100} = 4 \times 10^{-4}$.
$[H^+] = 0.25 \times 4 \times 10^{-4} = 1 \times 10^{-4} \text{ M}$.
Step $2$: Calculate the $pH$ of the solution.
$pH = -\log[H^+]$
$pH = -\log(10^{-4}) = 4$.
166
ChemistryDifficultMCQMHT CET · 2026
The dissociation constant of a weak acid $HA$ is $1.5 \times 10^{-5}$. Find the percent dissociation of a solution containing $0.2 \text{ moles}$ of $HA$ in $2 \text{ liters}$ of solution. (in $\%$)
A
$1.22$
B
$0.86$
C
$1.50$
D
$2.10$

Solution

(A) Step $1$: Calculate the molar concentration $C$ of the solution.
$C = \frac{n}{V} = \frac{0.2 \text{ mol}}{2 \text{ L}} = 0.1 \text{ M}$.
Step $2$: Use the formula for the degree of dissociation $\alpha$ for a weak acid.
$\alpha = \sqrt{\frac{K_a}{C}} = \sqrt{\frac{1.5 \times 10^{-5}}{0.1}} = \sqrt{1.5 \times 10^{-4}} = 1.2247 \times 10^{-2}$.
Step $3$: Convert the degree of dissociation to percent dissociation.
$\text{Percent dissociation} = \alpha \times 100 = 1.2247 \times 10^{-2} \times 100 = 1.2247 \% \approx 1.22 \%$.
167
ChemistryDifficultMCQMHT CET · 2026
Calculate the $pOH$ of a $0.001 \text{ M } HCl$ solution.
A
$11$
B
$10$
C
$12$
D
$3$

Solution

(A) Step $1$: $HCl$ is a strong acid and dissociates completely as $HCl \rightarrow H^+ + Cl^-$.
Step $2$: The concentration of $[H^+]$ is $0.001 \text{ M} = 10^{-3} \text{ M}$.
Step $3$: Calculate $pH$ using the formula $pH = -\log[H^+] = -\log(10^{-3}) = 3$.
Step $4$: Use the relation $pH + pOH = 14$ at $25^\circ \text{C}$.
Step $5$: $pOH = 14 - 3 = 11$.
168
ChemistryDifficultMCQMHT CET · 2026
What is the $pH$ of the resulting solution when $20 \text{ mL}$ of $\frac{M}{10} \text{ NaOH}$ and $10 \text{ mL}$ of $\frac{M}{10} \text{ H}_2\text{SO}_4$ are mixed together?
A
$0$
B
$2$
C
$7$
D
$10$

Solution

(C) Step $1$: Calculate moles of $OH^-$ ions from $\text{NaOH}$.
$\text{Moles of } OH^- = \text{Molarity} \times \text{Volume (in mL)} = 0.1 \text{ M} \times 20 \text{ mL} = 2 \text{ mmol}$.
Step $2$: Calculate moles of $H^+$ ions from $\text{H}_2\text{SO}_4$.
$\text{Moles of } H^+ = 2 \times \text{Molarity} \times \text{Volume (in mL)} = 2 \times 0.1 \text{ M} \times 10 \text{ mL} = 2 \text{ mmol}$.
Step $3$: Compare the moles of $H^+$ and $OH^-$.
Since the moles of $H^+$ $(2 \text{ mmol})$ are equal to the moles of $OH^-$ $(2 \text{ mmol})$, the solution is neutral.
Step $4$: Determine the $pH$.
For a neutral solution at $25^{\circ}\text{C}$, the $pH = 7$.
169
ChemistryDifficultMCQMHT CET · 2026
What is the molarity of $H_2SO_4$ solution having $pH = 4$?
A
$4 \times 10^{-1} \text{ M}$
B
$4 \times 10^{-2} \text{ M}$
C
$5 \times 10^{-5} \text{ M}$
D
$1 \times 10^{-4} \text{ M}$

Solution

(C) The concentration of hydrogen ions is given by $[H^+] = 10^{-pH} = 10^{-4} \text{ M}$.
Since $H_2SO_4$ is a strong diprotic acid, it dissociates as $H_2SO_4 \rightarrow 2H^+ + SO_4^{2-}$.
Therefore, the molarity of the $H_2SO_4$ solution is $[H_2SO_4] = \frac{[H^+]}{2}$.
$[H_2SO_4] = \frac{10^{-4}}{2} \text{ M} = 0.5 \times 10^{-4} \text{ M} = 5 \times 10^{-5} \text{ M}$.
170
ChemistryDifficultMCQMHT CET · 2026
An organic monobasic acid has a dissociation constant of $1.96 \times 10^{-8}$. What is its percentage dissociation in a $0.01 \text{ M}$ solution (in $\%$)?
A
$40$
B
$0.14$
C
$4$
D
$0.19$

Solution

(B) For a weak monobasic acid, the degree of dissociation $\alpha$ is given by $\alpha = \sqrt{K_a / C}$.
Given $K_a = 1.96 \times 10^{-8}$ and $C = 0.01 \text{ M}$.
$\alpha = \sqrt{\frac{1.96 \times 10^{-8}}{0.01}} = \sqrt{1.96 \times 10^{-6}} = 1.4 \times 10^{-3}$.
Percentage dissociation = $\alpha \times 100 = 1.4 \times 10^{-3} \times 100 = 0.14 \%$.
171
ChemistryDifficultMCQMHT CET · 2026
What is the $pH$ of a solution containing $5 \times 10^{-4} \text{ M } H^+$ ions?
A
$3.301$
B
$4.301$
C
$2.301$
D
$3.699$

Solution

(A) The formula for $pH$ is $pH = -\log[H^+]$.
Given $[H^+] = 5 \times 10^{-4} \text{ M}$.
$pH = -\log(5 \times 10^{-4})$.
$pH = -(\log 5 + \log 10^{-4})$.
$pH = -(\log 5 - 4)$.
$pH = 4 - \log 5$.
Since $\log 5 \approx 0.699$,
$pH = 4 - 0.699 = 3.301$.
172
ChemistryEasyMCQMHT CET · 2026
What is the normal $pH$ range of human blood?
A
$7.0$ to $7.2$
B
$7.35$ to $7.45$
C
$7.5$ to $7.8$
D
$6.8$ to $7.0$

Solution

(B) The normal $pH$ range of human blood is tightly regulated between $7.35$ and $7.45$ to maintain physiological homeostasis. Any value outside this range can lead to conditions like acidosis or alkalosis.
Therefore, the correct option is $B$.
173
ChemistryEasyMCQMHT CET · 2026
Which of the following ions are responsible for the hardness of water?
A
$Ag^+, Au^{3+}$ ions
B
$Hg^{2+}, Pb^{2+}$ ions
C
$Ca^{2+}$ and $Mg^{2+}$ ions
D
$As^{3+}, CN^-$ ions

Solution

(C) Hardness of water is primarily caused by the presence of dissolved calcium $(Ca^{2+})$ and magnesium $(Mg^{2+})$ ions in the water. These ions react with soap to form insoluble precipitates, preventing the formation of lather.
174
ChemistryMediumMCQMHT CET · 2026
What is the role of glycerol in the decomposition of $H_2O_2$?
A
It increases the reaction rate.
B
It reduces the reaction rate.
C
It increases the enthalpy of the reaction.
D
It increases the rate of collisions between reactant molecules.

Solution

(B) Step $1$: The decomposition of hydrogen peroxide $(H_2O_2)$ is a spontaneous reaction that is often catalyzed by impurities or light.
Step $2$: Glycerol acts as a negative catalyst or stabilizer in this reaction.
Step $3$: By adding glycerol, the rate of decomposition of $H_2O_2$ is significantly decreased, thereby stabilizing the solution.
Step $4$: Therefore, glycerol reduces the reaction rate.
175
ChemistryEasyMCQMHT CET · 2026
Which of the following is obtained when dihydrogen reacts with the alkali metals at high temperature?
A
Alkoxides
B
Metal hydrides
C
Peroxides
D
Metal nitrites

Solution

(B) Step $1$: Alkali metals $(M)$ react with dihydrogen $(H_2)$ at high temperatures to form ionic or saline hydrides.
Step $2$: The general chemical equation for this reaction is: $2M(s) + H_2(g) \xrightarrow{\Delta} 2MH(s)$, where $M$ represents an alkali metal.
Step $3$: Therefore, the product obtained is a metal hydride.
176
ChemistryEasyMCQMHT CET · 2026
Which of the following is the most abundant element in the universe?
A
$H$
B
$O$
C
$Ne$
D
$C$

Solution

(A) $1$. The universe is composed primarily of light elements formed during the Big Bang.
$2$. Hydrogen $(H)$ is the simplest and most abundant element, accounting for approximately $75\%$ of the baryonic mass of the universe.
$3$. Helium $(He)$ is the second most abundant, while other elements like Oxygen $(O)$, Carbon $(C)$, and Neon $(Ne)$ exist in much smaller quantities.
177
ChemistryEasyMCQMHT CET · 2026
The most abundant element in the universe is
A
$Hydrogen$
B
$Sodium$
C
$Magnesium$
D
$Potassium$

Solution

(A) $1$. The universe is primarily composed of light elements formed during the Big Bang.
$2$. $Hydrogen$ $(H)$ accounts for approximately $75\%$ of the elemental mass of the universe.
$3$. $Helium$ $(He)$ is the second most abundant, while all other elements are present in much smaller quantities.
$4$. Therefore, $Hydrogen$ is the most abundant element.
178
ChemistryEasyMCQMHT CET · 2026
Which of the following statements is $NOT$ correct regarding dihydrogen $(H_2)$?
A
It is a colorless and tasteless gas.
B
It burns with a pale blue flame.
C
It is a polar water-soluble gas.
D
It is lighter than air.

Solution

(C) $1$. Dihydrogen $(H_2)$ is a non-polar molecule because the electronegativity difference between the two hydrogen atoms is zero.
$2$. Due to its non-polar nature, it has very low solubility in water.
$3$. It is a colorless, odorless, and tasteless gas.
$4$. It is lighter than air and burns with a pale blue flame.
$5$. Therefore, the statement that it is a polar water-soluble gas is incorrect.
179
ChemistryEasyMCQMHT CET · 2026
Which of the following statements is false regarding hydrogen?
A
It has two isotopes.
B
In periodic table hydrogen is placed separately above group $1$.
C
When one electron is lost it forms a proton.
D
It does not exist freely.

Solution

(A) Step $1$: Hydrogen has three naturally occurring isotopes: protium $(^1H)$, deuterium ($^2H$ or $D$), and tritium ($^3H$ or $T$).
Step $2$: Statement $(A)$ claims it has two isotopes, which is false.
Step $3$: Statement $(B)$ is true as hydrogen's position is unique due to its properties.
Step $4$: Statement $(C)$ is true because $H - e^- \rightarrow H^+$, which is a proton.
Step $5$: Statement $(D)$ is true as hydrogen exists as a diatomic molecule $(H_2)$ in nature, not as a free atom.
180
ChemistryMediumMCQMHT CET · 2026
Which alkaline earth metal carbonate decomposes most easily?
A
$MgCO_3$
B
$CaCO_3$
C
$SrCO_3$
D
$BaCO_3$

Solution

(A) The thermal stability of alkaline earth metal carbonates increases down the group as the electropositive character of the metal increases.
$Mg^{2+}$ has the smallest ionic radius among the given options, which leads to high polarising power.
This high polarising power distorts the electron cloud of the carbonate ion $(CO_3^{2-})$ more effectively, weakening the $C-O$ bond.
Therefore, $MgCO_3$ requires the least amount of energy to decompose compared to $CaCO_3$, $SrCO_3$, and $BaCO_3$.
181
ChemistryEasyMCQMHT CET · 2026
Which of the following compounds is formed when chlorine gas reacts with dry slaked lime $Ca(OH)_2$?
A
$CaOCl_2$
B
$CaO_2Cl_2$
C
$CaOCl$
D
$CaCl_2$

Solution

(A) The reaction between chlorine gas and dry slaked lime $(Ca(OH)_2)$ produces bleaching powder $(CaOCl_2)$ and water $(H_2O)$.
The chemical equation is:
$Ca(OH)_2 + Cl_2 \rightarrow CaOCl_2 + H_2O$
Therefore, the compound formed is $CaOCl_2$.
182
ChemistryMediumMCQMHT CET · 2026
Choose the false statement regarding the properties of sodium hydroxide $(NaOH)$.
A
It is highly water soluble.
B
It absorbs atmospheric $CO_2$ to form $Na_2CO_3$.
C
The solution of $NaOH$ turns blue litmus red.
D
$NaOH$ is a white deliquescent solid.

Solution

(C) Step $1$: Sodium hydroxide $(NaOH)$ is a strong base.
Step $2$: Strong bases turn red litmus blue, not blue litmus red.
Step $3$: Therefore, the statement that $NaOH$ turns blue litmus red is false.
Step $4$: $NaOH$ is highly soluble in water, absorbs $CO_2$ from the atmosphere to form $Na_2CO_3$, and is a white deliquescent solid, making those statements true.
183
ChemistryMediumMCQMHT CET · 2026
Identify the elements of alkali metals and alkaline earth metals respectively having the highest $1^{st}$ ionization enthalpy.
A
$K$ and $Ca$
B
$Li$ and $Be$
C
$Rb$ and $Ba$
D
$K$ and $Sr$

Solution

(B) $1$. Ionization enthalpy decreases down a group as the atomic size increases and the valence electrons are further from the nucleus.
$2$. Alkali metals $(Group \ 1)$ follow the order: $Li > Na > K > Rb > Cs$. Thus, $Li$ has the highest $1^{st}$ ionization enthalpy.
$3$. Alkaline earth metals $(Group \ 2)$ follow the order: $Be > Mg > Ca > Sr > Ba$. Thus, $Be$ has the highest $1^{st}$ ionization enthalpy.
$4$. Therefore, the correct pair is $Li$ and $Be$.
184
ChemistryEasyMCQMHT CET · 2026
Identify the alkali metal having the smallest atomic size from the following.
A
Sodium
B
Potassium
C
Rubidium
D
Caesium

Solution

(A) $1$. Alkali metals belong to Group $1$ of the periodic table.
$2$. The order of elements in Group $1$ from top to bottom is $Li, Na, K, Rb, Cs, Fr$.
$3$. Atomic size increases down a group due to the addition of new electron shells.
$4$. Among the given options, $Na$ $(Z=11)$ is the highest in the group, followed by $K$ $(Z=19)$, $Rb$ $(Z=37)$, and $Cs$ $(Z=55)$.
$5$. Therefore, $Na$ has the smallest atomic size among the given options.
185
ChemistryMediumMCQMHT CET · 2026
Which of the following metal chlorides does not contain water of crystallisation?
A
$LiCl$
B
$MgCl_2$
C
$CsCl$
D
$BeCl_2$

Solution

(C) $1$. Water of crystallisation is the fixed number of water molecules present in one formula unit of a salt.
$2$. Small, highly charged cations like $Li^+$, $Mg^{2+}$, and $Be^{2+}$ have high hydration energy and tend to form hydrated salts (e.g., $LiCl \cdot H_2O$, $MgCl_2 \cdot 6H_2O$, $BeCl_2 \cdot 4H_2O$).
$3$. $Cs^+$ is a large cation with low charge density, resulting in low hydration energy. Therefore, $CsCl$ crystallises as an anhydrous salt.
$4$. Thus, $CsCl$ does not contain water of crystallisation.
186
ChemistryEasyMCQMHT CET · 2026
What is the general formula of halide salts of alkali metals if $M$ is a metal atom and $X$ is a halogen atom?
A
$MX$
B
$MX_2$
C
$M_3X_2$
D
$M_2X_3$

Solution

(A) $1$. Alkali metals belong to Group $1$ of the periodic table and have a valence shell electronic configuration of $ns^1$.
$2$. Alkali metals lose one electron to form a unipositive ion, $M^+$.
$3$. Halogens belong to Group $17$ and have a valence shell electronic configuration of $ns^2 np^5$, requiring one electron to complete their octet, forming a halide ion, $X^-$.
$4$. Combining $M^+$ and $X^-$ in a $1:1$ ratio to maintain electrical neutrality results in the formula $MX$.
187
ChemistryEasyMCQMHT CET · 2026
Which of the following elements forms a superoxide when it reacts with oxygen?
A
$Sodium$
B
$Potassium$
C
$Lithium$
D
$Magnesium$

Solution

(B) $1$. Alkali metals react with oxygen to form different types of oxides depending on their size.
$2$. $Lithium$ forms only monoxide $(Li_2O)$.
$3$. $Sodium$ forms peroxide $(Na_2O_2)$.
$4$. $Potassium$, $Rubidium$, and $Cesium$ form superoxides $(MO_2)$ due to the stabilization of the large anion by the large cation.
$5$. Therefore, $Potassium$ is the correct answer.
188
ChemistryEasyMCQMHT CET · 2026
What is the chemical formula of Tin $(IV)$ oxide?
A
$Sn_2O_3$
B
$SnO_2$
C
$SnO_4$
D
$SnO$

Solution

(B) Step $1$: Identify the symbols and valencies of the elements. Tin $(IV)$ has a valency of $+4$ $(Sn^{4+})$ and Oxide has a valency of $-2$ $(O^{2-})$.
Step $2$: Use the criss-cross method to determine the formula. The subscript of $Sn$ becomes $2$ and the subscript of $O$ becomes $4$, resulting in $Sn_2O_4$.
Step $3$: Simplify the ratio of the subscripts to the lowest whole number. Dividing both by $2$ gives $SnO_2$.
189
ChemistryEasyMCQMHT CET · 2026
Which of the following is $NOT$ a polymorphic form of silica $(SiO_2)$?
A
Cristobalite
B
$ \alpha $-quartz
C
$ \beta $-quartz
D
Aragonite

Solution

(D) $1$. Silica $(SiO_2)$ exists in several polymorphic forms such as quartz, tridymite, and cristobalite.
$2$. Quartz exists in different temperature-dependent forms, specifically $ \alpha $-quartz and $ \beta $-quartz.
$3$. Aragonite is a polymorphic form of calcium carbonate $(CaCO_3)$, not silica.
$4$. Therefore, Aragonite is not a polymorphic form of silica.
190
ChemistryEasyMCQMHT CET · 2026
Identify the catalyst used to transform carbon monoxide from water gas into carbon dioxide.
A
$K_2Cr_2O_7$
B
$Na_2CrO_4$
C
$FeCrO_4$
D
$Ni$

Solution

(C) The reaction is known as the water-gas shift reaction: $CO(g) + H_2O(g) \xrightarrow{FeCrO_4} CO_2(g) + H_2(g)$.
In this process, carbon monoxide from water gas is reacted with steam in the presence of an iron chromate $(FeCrO_4)$ catalyst to produce carbon dioxide and hydrogen.
191
ChemistryEasyMCQMHT CET · 2026
What is the nature of $Al_2O_3$?
A
Acidic
B
Basic
C
Amphoteric
D
Neutral

Solution

(C) $Al_2O_3$ is an amphoteric oxide because it reacts with both acids and bases to form salt and water.
Reaction with acid: $Al_2O_3 + 6HCl \rightarrow 2AlCl_3 + 3H_2O$
Reaction with base: $Al_2O_3 + 2NaOH + 3H_2O \rightarrow 2Na[Al(OH)_4]$
192
ChemistryEasyMCQMHT CET · 2026
Which of the following oxides is amphoteric in nature?
A
$BaO$
B
$N_2O_5$
C
$CO_2$
D
$Al_2O_3$

Solution

(D) $1$. Amphoteric oxides are those that can react with both acids and bases to form salt and water.
$2$. $BaO$ is a metallic oxide and is basic in nature.
$3$. $N_2O_5$ and $CO_2$ are non-metallic oxides and are acidic in nature.
$4$. $Al_2O_3$ reacts with both $HCl$ (acid) and $NaOH$ (base), hence it is amphoteric in nature.
193
ChemistryMediumMCQMHT CET · 2026
What type of isomerism is exhibited by neopentane $(C_5H_{12})$?
A
position isomerism
B
chain isomerism
C
geometrical isomerism
D
tautomerism

Solution

(B) $1$. Neopentane $(2,2-\text{dimethylpropane})$ has the molecular formula $C_5H_{12}$.
$2$. It is an isomer of $n-\text{pentane}$ and isopentane.
$3$. These isomers differ in the arrangement of the carbon chain (straight chain vs. branched chain).
$4$. Therefore, neopentane exhibits chain isomerism.
194
ChemistryDifficultMCQMHT CET · 2026
How many chiral carbon atoms are present in $2\text{-Iodo-}3,4,5\text{-trimethylhexane}$?
A
$2$
B
$3$
C
$4$
D
$1$

Solution

(B) $1$. The structure of $2\text{-Iodo-}3,4,5\text{-trimethylhexane}$ is $CH_3-CH(I)-CH(CH_3)-CH(CH_3)-CH(CH_3)-CH_3$.
$2$. $A$ chiral carbon atom is a carbon atom bonded to four different groups.
$3$. Let us examine each carbon atom:
- $C2$: Bonded to $-H, -I, -CH_3$, and $-CH(CH_3)CH(CH_3)CH(CH_3)CH_3$. This is chiral.
- $C3$: Bonded to $-H, -CH_3, -CH(I)CH_3$, and $-CH(CH_3)CH(CH_3)CH_3$. This is chiral.
- $C4$: Bonded to $-H, -CH_3, -CH(CH_3)CH(I)CH_3$, and $-CH(CH_3)CH_3$. This is chiral.
- $C5$: Bonded to $-H, -CH_3, -CH_3$, and $-CH(CH_3)CH(CH_3)CH(I)CH_3$. Since it is bonded to two identical $-CH_3$ groups, it is achiral.
$4$. Thus, there are $3$ chiral carbon atoms $(C2, C3, C4)$.
195
ChemistryDifficultMCQMHT CET · 2026
What is the number of chiral carbon atoms present in $2$-Bromo-$3,4,5$-trimethylhexane?
A
$1$
B
$2$
C
$3$
D
$4$

Solution

(D) The structure of $2$-Bromo-$3,4,5$-trimethylhexane is $CH_3-CH(Br)-CH(CH_3)-CH(CH_3)-CH(CH_3)-CH_3$.
Identify the chiral carbons (carbons attached to four different groups):
$(1)$ $C_2$: Attached to $-H$, $-Br$, $-CH_3$, and $-CH(CH_3)CH(CH_3)CH_2CH_3$. This is chiral.
$(2)$ $C_3$: Attached to $-H$, $-CH_3$, $-CH(Br)CH_3$, and $-CH(CH_3)CH_2CH_3$. This is chiral.
$(3)$ $C_4$: Attached to $-H$, $-CH_3$, $-CH(CH_3)CH(Br)CH_3$, and $-CH_2CH_3$. This is chiral.
$(4)$ $C_5$: Attached to $-H$, $-CH_3$, $-CH_2CH_3$, and $-CH(CH_3)CH(CH_3)CH(Br)CH_3$. This is chiral.
All four carbons at positions $2, 3, 4,$ and $5$ are chiral.
Therefore, the total number of chiral carbon atoms is $4$.
196
ChemistryMediumMCQMHT CET · 2026
What is the number of chiral carbon atoms in $2$-chlorobutane?
A
$4$
B
$3$
C
$2$
D
$1$

Solution

(D) The structure of $2$-chlorobutane is $CH_3-CHCl-CH_2-CH_3$.
$A$ chiral carbon atom is a carbon atom bonded to four different groups.
In $2$-chlorobutane, the carbon at position $2$ is bonded to:
$1$. $A$ hydrogen atom $(-H)$
$2$. $A$ chlorine atom $(-Cl)$
$3$. $A$ methyl group $(-CH_3)$
$4$. An ethyl group $(-CH_2CH_3)$
Since all four groups are different, the carbon at position $2$ is chiral.
There is only $1$ chiral carbon atom in the molecule.
197
ChemistryMediumMCQMHT CET · 2026
Find the number of structural isomers possible for hexane $(C_6H_{14})$?
A
Two
B
Four
C
Three
D
Five

Solution

(D) The structural isomers of hexane $(C_6H_{14})$ are:
$1$. $n$-hexane: $CH_3-CH_2-CH_2-CH_2-CH_2-CH_3$
$2$. $2$-methylpentane: $CH_3-CH(CH_3)-CH_2-CH_2-CH_3$
$3$. $3$-methylpentane: $CH_3-CH_2-CH(CH_3)-CH_2-CH_3$
$4$. $2,2$-dimethylbutane: $CH_3-C(CH_3)_2-CH_2-CH_3$
$5$. $2,3$-dimethylbutane: $CH_3-CH(CH_3)-CH(CH_3)-CH_3$
There are a total of $5$ structural isomers.
198
ChemistryMediumMCQMHT CET · 2026
Which of the following molecules has a chiral carbon atom?
A
Option A
B
Option B
C
Option C
D
Option D

Solution

(B) chiral carbon atom is a carbon atom bonded to four different groups or atoms. Let us analyze each option:
$(A)$ The central carbon is bonded to $-H$, $-H$, $-Cl$, and $-Br$. Since two groups $(-H)$ are identical, it is not chiral.
$(B)$ The central carbon is bonded to $-H$, $-CH_3$, $-OH$, and $-I$. All four groups are different, so this carbon is chiral.
$(C)$ The central carbon is bonded to $-CH_3$, $-CH_3$, $-Cl$, and $-Br$. Since two groups $(-CH_3)$ are identical, it is not chiral.
$(D)$ The central carbon is bonded to $-H$, $-Cl$, $-C_2H_5$, and $-C_2H_5$. Since two groups $(-C_2H_5)$ are identical, it is not chiral.
Therefore, the molecule in option $(B)$ contains a chiral carbon atom.
199
ChemistryMediumMCQMHT CET · 2026
Which of the following has the highest nucleophilicity?
A
$F^-$
B
$OH^-$
C
$CH_3^-$
D
$NH_2^-$

Solution

(C) Nucleophilicity is related to the ability of a species to donate an electron pair. In a given period of the periodic table, nucleophilicity decreases as electronegativity increases.
Comparing the atoms $C$, $N$, $O$, and $F$ in the second period:
Electronegativity order: $C < N < O < F$.
Therefore, the basicity and nucleophilicity order is: $CH_3^- > NH_2^- > OH^- > F^-$.
Thus, $CH_3^-$ is the strongest nucleophile among the given options.
200
ChemistryMediumMCQMHT CET · 2026
Which one of the following series contains only electrophiles?
A
$R-OH, Cl^+, NH_3$
B
$H_2O, R_2N^-, H_3O^+$
C
$BF_3, SO_3, NO^+$
D
$AlCl_3, R-NH_2, PCl_3$

Solution

(C) $1$. An electrophile is an electron-deficient species that can accept an electron pair.
$2$. In option $C$, $BF_3$ is an electron-deficient molecule (octet incomplete), $SO_3$ has an electron-deficient sulfur atom due to electronegative oxygen atoms, and $NO^+$ is a positively charged ion.
$3$. All three species in option $C$ act as electrophiles.
$4$. Other options contain nucleophiles like $NH_3$, $R_2N^-$, $R-NH_2$, and $PCl_3$ (which has a lone pair).
201
ChemistryMediumMCQMHT CET · 2026
Which of the following colligative properties is useful to determine the molar masses of proteins, polymers, or colloids with the greatest precision?
A
Elevation in boiling point
B
Depression in freezing point
C
Osmotic pressure
D
Relative lowering of vapour pressure

Solution

(C) Step $1$: The molar mass of macromolecules like proteins and polymers is very high.
Step $2$: For these substances, the values of other colligative properties like elevation in boiling point or depression in freezing point are too small to be measured accurately.
Step $3$: Osmotic pressure $(\pi)$ is given by the equation $\pi = CRT = \frac{n}{V}RT = \frac{w}{MV}RT$. Even for dilute solutions of macromolecules, the osmotic pressure value is large enough to be measured with high precision.
Step $4$: Therefore, osmotic pressure is the most suitable method for determining the molar masses of such substances.
202
ChemistryDifficultMCQMHT CET · 2026
If a $0.4 \text{ molal}$ solution of a nonvolatile solute in an organic solvent decreases its freezing point by $2.4 \text{ K}$, then the molal depression constant $(K_f)$ of the solvent will be:
A
$3.0 \text{ K kg mol}^{-1}$
B
$4.0 \text{ K kg mol}^{-1}$
C
$5.0 \text{ K kg mol}^{-1}$
D
$6.0 \text{ K kg mol}^{-1}$

Solution

(D) The formula for freezing point depression is $\Delta T_f = K_f \times m$, where $\Delta T_f$ is the depression in freezing point, $K_f$ is the molal depression constant, and $m$ is the molality of the solution.
Given:
$\Delta T_f = 2.4 \text{ K}$
$m = 0.4 \text{ mol kg}^{-1}$
Substituting the values into the formula:
$2.4 \text{ K} = K_f \times 0.4 \text{ mol kg}^{-1}$
$K_f = \frac{2.4 \text{ K}}{0.4 \text{ mol kg}^{-1}}$
$K_f = 6.0 \text{ K kg mol}^{-1}$
Therefore, the correct option is $D$.
203
ChemistryEasyMCQMHT CET · 2026
Which of the following is a colligative property of a solution?
A
Vapour pressure
B
Boiling point
C
Osmotic pressure
D
Freezing point

Solution

(C) $1$. Colligative properties are properties of solutions that depend only on the number of solute particles present in a given amount of solvent, not on their identity.
$2$. Common colligative properties include relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, and osmotic pressure.
$3$. Among the given options, $osmotic \ pressure$ is a colligative property, whereas vapour pressure, boiling point, and freezing point are properties that change due to the presence of solute but are not colligative properties themselves (their changes are).
204
ChemistryDifficultMCQMHT CET · 2026
Calculate the boiling point of an aqueous solution containing $18 \text{ g}$ of glucose in $100 \text{ g}$ of water, given that the molal elevation constant $(K_b)$ of water is $0.5 \text{ K kg mol}^{-1}$. [Molar mass of glucose $= 180 \text{ g mol}^{-1}$ and boiling point of pure water $= 100^{\circ}\text{C}$] (in $^{\circ}\text{C}$)
A
$100$
B
$100.5$
C
$101.0$
D
$101.5$

Solution

(B) Step $1$: Calculate the number of moles of glucose $(n)$: $n = \frac{\text{mass}}{\text{molar mass}} = \frac{18 \text{ g}}{180 \text{ g mol}^{-1}} = 0.1 \text{ mol}$.
Step $2$: Calculate the molality $(m)$ of the solution: $m = \frac{\text{moles of solute}}{\text{mass of solvent in kg}} = \frac{0.1 \text{ mol}}{0.1 \text{ kg}} = 1 \text{ mol kg}^{-1}$.
Step $3$: Calculate the elevation in boiling point $(\Delta T_b)$: $\Delta T_b = K_b \times m = 0.5 \text{ K kg mol}^{-1} \times 1 \text{ mol kg}^{-1} = 0.5 \text{ K}$ (or $0.5^{\circ}\text{C}$).
Step $4$: Calculate the boiling point of the solution: $T_b = T_b^{\circ} + \Delta T_b = 100^{\circ}\text{C} + 0.5^{\circ}\text{C} = 100.5^{\circ}\text{C}$.
205
ChemistryDifficultMCQMHT CET · 2026
$18 \text{ g}$ of glucose (molar mass $= 180 \text{ g/mol}$) is dissolved in water to prepare $500 \text{ ml}$ solution at $15^{\circ}\text{C}$. Calculate the osmotic pressure of the solution. $[R = 0.0821 \text{ L atm K}^{-1} \text{ mol}^{-1}]$ (in $\text{ atm}$)
A
$1.65$
B
$4.73$
C
$5.57$
D
$2.34$

Solution

(B) Step $1$: Calculate the number of moles of glucose $(n)$: $n = \frac{\text{mass}}{\text{molar mass}} = \frac{18 \text{ g}}{180 \text{ g/mol}} = 0.1 \text{ mol}$.
Step $2$: Convert volume to liters $(V)$: $V = 500 \text{ ml} = 0.5 \text{ L}$.
Step $3$: Convert temperature to Kelvin $(T)$: $T = 15 + 273.15 = 288.15 \text{ K}$.
Step $4$: Use the osmotic pressure formula $\pi = CRT = \frac{n}{V}RT$: $\pi = \frac{0.1 \text{ mol}}{0.5 \text{ L}} \times 0.0821 \text{ L atm K}^{-1} \text{ mol}^{-1} \times 288.15 \text{ K} = 0.2 \times 0.0821 \times 288.15 = 4.732 \text{ atm}$.
Thus, the osmotic pressure is approximately $4.73 \text{ atm}$.
206
ChemistryDifficultMCQMHT CET · 2026
The normal boiling point of ethyl acetate is $77^{\circ}\text{C}$. $A$ solution of a non-volatile, non-electrolyte solute in ethyl acetate boils at $78^{\circ}\text{C}$. The $K_b$ for ethyl acetate is $2.77^{\circ}\text{C kg mol}^{-1}$. What is the molality of the solution (in $\text{ m}$)?
A
$0.361$
B
$0.052$
C
$0.075$
D
$0.25$

Solution

(A) Step $1$: Calculate the elevation in boiling point $(\Delta T_b)$.
$\Delta T_b = T_b - T_b^{\circ} = 78^{\circ}\text{C} - 77^{\circ}\text{C} = 1^{\circ}\text{C}$.
Step $2$: Use the formula for elevation in boiling point: $\Delta T_b = K_b \times m$.
Step $3$: Rearrange to solve for molality $(m)$: $m = \frac{\Delta T_b}{K_b}$.
Step $4$: Substitute the values: $m = \frac{1}{2.77} \approx 0.361\text{ m}$.
207
ChemistryDifficultMCQMHT CET · 2026
Calculate the molar mass of a non-volatile solute when $4 \text{ g}$ of it is dissolved in $100 \text{ g}$ of a solvent that boils at $319.4 \text{ K}$. Given: $K_b = 2.4 \text{ K kg mol}^{-1}$ and the boiling point of the pure solvent is $319 \text{ K}$.
A
$220 \text{ g mol}^{-1}$
B
$230 \text{ g mol}^{-1}$
C
$240 \text{ g mol}^{-1}$
D
$250 \text{ g mol}^{-1}$

Solution

(C) Step $1$: Calculate the elevation in boiling point $\Delta T_b = T_b - T_b^\circ = 319.4 \text{ K} - 319 \text{ K} = 0.4 \text{ K}$.
Step $2$: Use the formula $\Delta T_b = K_b \times m$, where $m$ is molality.
Step $3$: Molality $m = \frac{w_2 \times 1000}{M_2 \times w_1}$, where $w_2 = 4 \text{ g}$, $w_1 = 100 \text{ g}$, and $M_2$ is the molar mass of the solute.
Step $4$: Substitute the values: $0.4 = 2.4 \times \frac{4 \times 1000}{M_2 \times 100}$.
Step $5$: Simplify: $0.4 = 2.4 \times \frac{40}{M_2} \implies 0.4 = \frac{96}{M_2}$.
Step $6$: Solve for $M_2$: $M_2 = \frac{96}{0.4} = 240 \text{ g mol}^{-1}$.
208
ChemistryDifficultMCQMHT CET · 2026
Calculate the van't Hoff factor $(i)$ for an aqueous solution of $0.02 \text{ m}$ formic acid if it freezes at $-0.045^{\circ}\text{C}$. Given: $K_f = 1.86 \text{ K kg mol}^{-1}$ and the freezing point of pure water $= 0^{\circ}\text{C}$.
A
$1.21$
B
$1.46$
C
$1.68$
D
$1.05$

Solution

(A) Step $1$: Calculate the depression in freezing point $(\Delta T_f)$.
$\Delta T_f = T_f^{\circ} - T_f = 0^{\circ}\text{C} - (-0.045^{\circ}\text{C}) = 0.045 \text{ K}$.
Step $2$: Use the formula for depression in freezing point: $\Delta T_f = i \times K_f \times m$.
Step $3$: Substitute the given values: $0.045 = i \times 1.86 \times 0.02$.
Step $4$: Solve for $i$: $i = \frac{0.045}{1.86 \times 0.02} = \frac{0.045}{0.0372} \approx 1.21$.
209
ChemistryMediumMCQMHT CET · 2026
Which of the following concentrations of solutions of urea in water exhibits minimum freezing point depression (in $\text{ m}$)?
A
$0.12$
B
$0.18$
C
$0.08$
D
$0.06$

Solution

(D) The freezing point depression $\Delta T_f$ is given by the formula $\Delta T_f = i \cdot K_f \cdot m$.
For urea, which is a non-electrolyte, the van't Hoff factor $i = 1$.
Thus, $\Delta T_f = K_f \cdot m$.
Since $K_f$ is a constant for the solvent (water), $\Delta T_f$ is directly proportional to the molality $m$ of the solution.
To obtain the minimum freezing point depression, we must choose the solution with the minimum molality.
Comparing the given concentrations: $0.12 \text{ m}$, $0.18 \text{ m}$, $0.08 \text{ m}$, and $0.06 \text{ m}$, the smallest value is $0.06 \text{ m}$.
Therefore, the solution with $0.06 \text{ m}$ concentration exhibits the minimum freezing point depression.
210
ChemistryMediumMCQMHT CET · 2026
Identify the correct statement from the following.
A
The vapour pressure of a solvent increases by dissolving a non-volatile solute into it.
B
The boiling point of a solvent decreases by dissolving a non-volatile solute into it.
C
The osmotic pressure of an electrolytic solution is greater than a non-electrolytic solution of the same concentration.
D
The freezing point of a solvent is a colligative property.

Solution

(C) $1$. According to Raoult's law, adding a non-volatile solute decreases the vapour pressure of the solvent.
$2$. The decrease in vapour pressure leads to an elevation in the boiling point of the solvent.
$3$. Osmotic pressure is a colligative property, which depends on the number of particles. Electrolytes dissociate into multiple ions, increasing the number of particles compared to non-electrolytes at the same concentration, thus resulting in higher osmotic pressure.
$4$. Freezing point depression is a colligative property, but the freezing point itself is not.
211
ChemistryDifficultMCQMHT CET · 2026
Calculate the cryoscopic constant $(K_f)$ of a solvent if the depression in freezing point of a $0.3 \text{ m}$ solution of a nonelectrolyte is $0.48 \text{ K}$.
A
$1.1 \text{ K kg mol}^{-1}$
B
$1.6 \text{ K kg mol}^{-1}$
C
$2.2 \text{ K kg mol}^{-1}$
D
$2.6 \text{ K kg mol}^{-1}$

Solution

(B) The formula for depression in freezing point is: $\Delta T_f = K_f \times m$
Given:
$\Delta T_f = 0.48 \text{ K}$
$m = 0.3 \text{ mol kg}^{-1}$
Rearranging the formula to solve for $K_f$:
$K_f = \frac{\Delta T_f}{m}$
$K_f = \frac{0.48 \text{ K}}{0.3 \text{ mol kg}^{-1}}$
$K_f = 1.6 \text{ K kg mol}^{-1}$
Thus, the correct option is $B$.
212
ChemistryDifficultMCQMHT CET · 2026
Calculate the molar mass of a nonvolatile solute if $6.4 \text{ g}$ of it dissolved in $100 \text{ g}$ water produces a relative lowering in vapour pressure of $0.016$ at $300 \text{ K}$.
A
$60 \text{ g mol}^{-1}$
B
$66 \text{ g mol}^{-1}$
C
$72 \text{ g mol}^{-1}$
D
$84 \text{ g mol}^{-1}$

Solution

(C) The relative lowering in vapour pressure is given by Raoult's Law: $\frac{P^\circ - P_s}{P^\circ} = \frac{n_2}{n_1 + n_2} \approx \frac{n_2}{n_1}$ for dilute solutions.
Given: $\frac{P^\circ - P_s}{P^\circ} = 0.016$, mass of solute $w_2 = 6.4 \text{ g}$, mass of solvent $w_1 = 100 \text{ g}$, molar mass of water $M_1 = 18 \text{ g mol}^{-1}$.
Formula: $\frac{P^\circ - P_s}{P^\circ} = \frac{w_2 \times M_1}{M_2 \times w_1}$.
Substitute the values: $0.016 = \frac{6.4 \times 18}{M_2 \times 100}$.
$M_2 = \frac{6.4 \times 18}{0.016 \times 100} = \frac{115.2}{1.6} = 72 \text{ g mol}^{-1}$.
213
ChemistryMediumMCQMHT CET · 2026
Identify the correct statement regarding $0.2 \text{ M}$ urea and $0.2 \text{ M}$ sucrose solutions.
A
The urea solution is hypertonic to the sucrose solution.
B
The osmotic pressure of the urea solution is higher than that of the sucrose solution.
C
These solutions exhibit the same osmotic pressure.
D
The sucrose solution is hypotonic to the urea solution.

Solution

(C) Step $1$: Osmotic pressure $(\pi)$ is given by the formula $\pi = iCRT$, where $i$ is the van't Hoff factor, $C$ is molarity, $R$ is the gas constant, and $T$ is temperature.
Step $2$: For urea $(NH_2CONH_2)$, $i = 1$ (non-electrolyte). For sucrose $(C_{12}H_{22}O_{11})$, $i = 1$ (non-electrolyte).
Step $3$: Both solutions have the same molarity $(C = 0.2 \text{ M})$. Since $i$, $C$, $R$, and $T$ are identical for both, their osmotic pressures are equal.
Step $4$: Solutions with the same osmotic pressure are called isotonic solutions. Thus, statement $(c)$ is correct.
214
ChemistryDifficultMCQMHT CET · 2026
Calculate the molality of a solution of a non-volatile solute if the boiling point of the solution and the molal elevation constant for the solvent are $319.8 \text{ K}$ and $2.5 \text{ K kg mol}^{-1}$ respectively. [Boiling point of pure solvent $= 319.5 \text{ K}$]
A
$0.12 \text{ mol kg}^{-1}$
B
$0.14 \text{ mol kg}^{-1}$
C
$0.17 \text{ mol kg}^{-1}$
D
$0.21 \text{ mol kg}^{-1}$

Solution

(A) Step $1$: Calculate the elevation in boiling point $(\Delta T_b)$.
$\Delta T_b = T_b - T_b^\circ = 319.8 \text{ K} - 319.5 \text{ K} = 0.3 \text{ K}$.
Step $2$: Use the formula for elevation in boiling point: $\Delta T_b = K_b \times m$.
Step $3$: Rearrange to solve for molality $(m)$:
$m = \frac{\Delta T_b}{K_b} = \frac{0.3 \text{ K}}{2.5 \text{ K kg mol}^{-1}} = 0.12 \text{ mol kg}^{-1}$.
215
ChemistryMediumMCQMHT CET · 2026
Which of the following options is true when an electrolyte solution is diluted?
A
both $\Lambda_m$ and $\kappa$ increase
B
both $\Lambda_m$ and $\kappa$ decrease
C
$\Lambda_m$ increases and $\kappa$ decreases
D
$\Lambda_m$ decreases and $\kappa$ increases

Solution

(C) $1$. Molar conductivity $(\Lambda_m)$ is defined as $\Lambda_m = \frac{\kappa}{C}$. As the solution is diluted, the concentration $(C)$ decreases, which leads to an increase in the number of ions per unit volume available for conduction, causing $\Lambda_m$ to increase.
$2$. Conductivity $(\kappa)$ is defined as the conductance of a solution contained between two electrodes of unit area and unit distance apart. Upon dilution, the number of ions per unit volume decreases, which leads to a decrease in conductivity $(\kappa)$.
$3$. Therefore, upon dilution, $\Lambda_m$ increases and $\kappa$ decreases.
216
ChemistryEasyMCQMHT CET · 2026
Identify the correct name of the law: "At infinite dilution, each ion migrates independently of its co-ion and contributes to the total molar conductivity of an electrolyte, irrespective of the nature of the other ion to which it is associated."
A
Henry's law
B
Raoult's law
C
Nernst derivative law
D
Kohlrausch's law of independent migration of ions

Solution

(D) Step $1$: The statement describes the behavior of ions in an electrolytic solution at infinite dilution.
Step $2$: According to Kohlrausch's law of independent migration of ions, at infinite dilution, where dissociation is complete, each ion makes a definite contribution to the molar conductivity of the electrolyte, which is independent of the presence of other ions.
Step $3$: Therefore, the correct law is Kohlrausch's law.
217
ChemistryDifficultMCQMHT CET · 2026
Calculate the molar conductivity of $0.2 \text{ M}$ $KCl$ solution at $298 \text{ K}$ if the conductivity $(k)$ is $0.0248 \text{ } \Omega^{-1} \text{cm}^{-1}$.
A
$143 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
B
$98 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
C
$124 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
D
$87 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$

Solution

(C) The formula for molar conductivity $(\Lambda_m)$ is: $\Lambda_m = \frac{1000 \times k}{M}$
Given: Conductivity $(k)$ = $0.0248 \text{ } \Omega^{-1} \text{cm}^{-1}$, Molarity $(M)$ = $0.2 \text{ M}$.
Substituting the values: $\Lambda_m = \frac{1000 \times 0.0248}{0.2}$
$\Lambda_m = \frac{24.8}{0.2} = 124 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$.
218
ChemistryDifficultMCQMHT CET · 2026
The molar conductivity of a $0.04 \text{ M}$ $AB_2$ type salt solution at $300 \text{ K}$ is $200 \text{ } \Omega^{-1} \text{ cm}^2 \text{ mol}^{-1}$. Find the conductivity.
A
$0.006 \text{ } \Omega^{-1} \text{ cm}^{-1}$
B
$0.008 \text{ } \Omega^{-1} \text{ cm}^{-1}$
C
$0.01 \text{ } \Omega^{-1} \text{ cm}^{-1}$
D
$0.015 \text{ } \Omega^{-1} \text{ cm}^{-1}$

Solution

(B) The relationship between molar conductivity $(\Lambda_m)$ and conductivity $(\kappa)$ is given by the formula: $\Lambda_m = \frac{\kappa \times 1000}{M}$.
Rearranging for conductivity $(\kappa)$: $\kappa = \frac{\Lambda_m \times M}{1000}$.
Given: $\Lambda_m = 200 \text{ } \Omega^{-1} \text{ cm}^2 \text{ mol}^{-1}$, $M = 0.04 \text{ M}$.
Substituting the values: $\kappa = \frac{200 \times 0.04}{1000}$.
$\kappa = \frac{8}{1000} = 0.008 \text{ } \Omega^{-1} \text{ cm}^{-1}$.
219
ChemistryDifficultMCQMHT CET · 2026
The molar conductivity of a $0.01 \text{ M}$ monobasic acid at $25^{\circ} \text{C}$ is $15 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$. The molar conductivity of the same acid at infinite dilution is $375 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$. Calculate the concentration of $[H^+]$ in the solution.
A
$2.0 \times 10^{-4} \text{ M}$
B
$3.0 \times 10^{-4} \text{ M}$
C
$4.0 \times 10^{-4} \text{ M}$
D
$5.0 \times 10^{-4} \text{ M}$

Solution

(C) Step $1$: Calculate the degree of dissociation $(\alpha)$ using the formula $\alpha = \frac{\Lambda_m}{\Lambda_m^\circ}$.
$\alpha = \frac{15}{375} = 0.04$.
Step $2$: Calculate the concentration of $[H^+]$ using the relation $[H^+] = C \times \alpha$.
Given $C = 0.01 \text{ M}$.
$[H^+] = 0.01 \times 0.04 = 4 \times 10^{-4} \text{ M}$.
220
ChemistryDifficultMCQMHT CET · 2026
Calculate the concentration of silver nitrate solution if molar conductivity and conductivity of silver nitrate at $25^{\circ} \text{C}$ are respectively $120 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$ and $0.0024 \text{ } \Omega^{-1} \text{cm}^{-1}$. (in $\text{ M}$)
A
$0.01$
B
$0.02$
C
$0.03$
D
$0.04$

Solution

(B) The relationship between molar conductivity $(\Lambda_m)$, conductivity $(k)$, and molarity $(M)$ is given by: $\Lambda_m = \frac{1000 \times k}{M}$.
Rearranging for molarity: $M = \frac{1000 \times k}{\Lambda_m}$.
Given: $k = 0.0024 \text{ } \Omega^{-1} \text{cm}^{-1}$ and $\Lambda_m = 120 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$.
Substituting the values: $M = \frac{1000 \times 0.0024}{120}$.
$M = \frac{2.4}{120} = 0.02 \text{ M}$.
221
ChemistryMediumMCQMHT CET · 2026
The graphical variation of molar conductivity $(\Lambda_m)$ against the square root of molar concentration $(\sqrt{c})$ for a certain electrolyte '$X$' is linear with an intercept on the y-axis. Identify '$X$' from the following.
A
$CH_3COOH$
B
$NH_4OH$
C
$HCOOH$
D
$CH_3COONa$

Solution

(D) $1$. According to the Kohlrausch law and the Debye-$H$ückel-Onsager equation, strong electrolytes show a linear relationship between molar conductivity $(\Lambda_m)$ and $\sqrt{c}$ given by $\Lambda_m = \Lambda_m^\circ - A\sqrt{c}$, where $\Lambda_m^\circ$ is the intercept on the y-axis.
$2$. Weak electrolytes like $CH_3COOH$, $NH_4OH$, and $HCOOH$ show a non-linear curve that increases sharply as concentration approaches zero.
$3$. $CH_3COONa$ is a strong electrolyte, which dissociates completely in solution, thus following the linear relationship.
$4$. Therefore, '$X$' is $CH_3COONa$.
222
ChemistryDifficultMCQMHT CET · 2026
The conductivity of $0.02 \text{ M}$ $KCl$ solution at $298 \text{ K}$ is $0.0123 \text{ } \Omega^{-1} \text{ cm}^{-1}$. If the resistance of the cell containing this solution is $120 \text{ } \Omega$, what is the value of the cell constant (in $\text{ cm}^{-1}$)?
A
$1.050$
B
$1.025$
C
$1.376$
D
$1.476$

Solution

(D) The cell constant $(G^*)$ is given by the formula: $G^* = \kappa \times R$
Given conductivity $(\kappa)$ = $0.0123 \text{ } \Omega^{-1} \text{ cm}^{-1}$
Given resistance $(R)$ = $120 \text{ } \Omega$
$G^* = 0.0123 \text{ } \Omega^{-1} \text{ cm}^{-1} \times 120 \text{ } \Omega$
$G^* = 1.476 \text{ cm}^{-1}$
223
ChemistryDifficultMCQMHT CET · 2026
What is the conductivity of $0.02 \text{ M}$ $AgNO_3$ solution having cell constant $1.2 \text{ cm}^{-1}$ and resistance $95.0 \text{ } \Omega$?
A
$1.263 \times 10^{-2} \text{ } \Omega^{-1} \text{cm}^{-1}$
B
$1.263 \text{ } \Omega^{-1} \text{cm}^{-1}$
C
$1.340 \text{ } \Omega^{-1} \text{cm}^{-1}$
D
$1.463 \text{ } \Omega^{-1} \text{cm}^{-1}$

Solution

(A) The formula for conductivity $(\kappa)$ is given by: $\kappa = \frac{G^*}{R}$
Given: Cell constant $(G^*)$ = $1.2 \text{ cm}^{-1}$, Resistance $(R)$ = $95.0 \text{ } \Omega$.
Substituting the values: $\kappa = \frac{1.2 \text{ cm}^{-1}}{95.0 \text{ } \Omega} = 0.01263 \text{ } \Omega^{-1} \text{cm}^{-1}$.
Therefore, $\kappa = 1.263 \times 10^{-2} \text{ } \Omega^{-1} \text{cm}^{-1}$.
224
ChemistryDifficultMCQMHT CET · 2026
What must be the molarity of $BaCl_2$ solution to have molar conductivity $240 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$ and conductivity $0.012 \text{ } \Omega^{-1} \text{cm}^{-1}$ at $25^{\circ} \text{C}$ (in $\text{ M}$)?
A
$0.01$
B
$0.02$
C
$0.05$
D
$0.1$

Solution

(C) The relationship between molar conductivity $(\Lambda_m)$, conductivity $(\kappa)$, and molarity $(M)$ is given by the formula:
$\Lambda_m = \frac{1000 \times \kappa}{M}$
Rearranging the formula to solve for molarity $(M)$:
$M = \frac{1000 \times \kappa}{\Lambda_m}$
Substitute the given values: $\kappa = 0.012 \text{ } \Omega^{-1} \text{cm}^{-1}$ and $\Lambda_m = 240 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$.
$M = \frac{1000 \times 0.012}{240}$
$M = \frac{12}{240} = 0.05 \text{ M}$
225
ChemistryDifficultMCQMHT CET · 2026
What is the molar conductivity of $CH_3COOH$ at infinite dilution if the molar conductivities of $H_2SO_4$, $K_2SO_4$, and $CH_3COOK$ at infinite dilution are $x$, $y$, and $z$ $\Omega^{-1} \text{cm}^2 \text{mol}^{-1}$ respectively?
A
$\frac{(x - y)}{2} + z$
B
$(x - y + 2z)$
C
$(x + y - z)$
D
$\frac{(x - y)}{2} + 2z$

Solution

(A) According to Kohlrausch's law:
$\Lambda^0_m(CH_3COOH) = \Lambda^0_m(CH_3COOK) + \Lambda^0_m(H^+) - \Lambda^0_m(K^+)$
We know that $\Lambda^0_m(H^+) = \frac{1}{2} \Lambda^0_m(H_2SO_4) = \frac{x}{2}$ and $\Lambda^0_m(K^+) = \frac{1}{2} \Lambda^0_m(K_2SO_4) = \frac{y}{2}$.
Substituting these values:
$\Lambda^0_m(CH_3COOH) = z + \frac{x}{2} - \frac{y}{2} = \frac{(x - y)}{2} + z$.
226
ChemistryDifficultMCQMHT CET · 2026
What is the molar conductivity of $0.02 \text{ M}$ $KI$ solution if its conductivity is $4.37 \times 10^{-4} \text{ } \Omega^{-1} \text{cm}^{-1}$?
A
$8.74 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
B
$21.85 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
C
$43.70 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
D
$13.65 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$

Solution

(B) The formula for molar conductivity $(\Lambda_m)$ is given by: $\Lambda_m = \frac{\kappa \times 1000}{C}$
Given conductivity $(\kappa)$ = $4.37 \times 10^{-4} \text{ } \Omega^{-1} \text{cm}^{-1}$
Given concentration $(C)$ = $0.02 \text{ M}$
Substituting the values: $\Lambda_m = \frac{4.37 \times 10^{-4} \times 1000}{0.02}$
$\Lambda_m = \frac{0.437}{0.02} = 21.85 \text{ } \Omega^{-1} \text{cm}^2 \text{mol}^{-1}$
227
ChemistryEasyMCQMHT CET · 2026
Which of the following expressions indicates the correct relationship between molar conductivity of a strong electrolyte and its concentration $c$?
A
$\Lambda_m = \Lambda_m^0 + \sqrt{c}$
B
$\Lambda_m = \Lambda_m^0 - A\sqrt{c}$
C
$\Lambda_m = \Lambda_m^0 + A\sqrt{c}$
D
$\Lambda_m = \Lambda_m^0 - \sqrt{c}$

Solution

(B) For strong electrolytes, the molar conductivity $\Lambda_m$ varies with the concentration $c$ according to the Kohlrausch equation:
$\Lambda_m = \Lambda_m^0 - A\sqrt{c}$
where $\Lambda_m^0$ is the molar conductivity at infinite dilution and $A$ is a constant that depends on the nature of the solvent and temperature.
228
ChemistryDifficultMCQMHT CET · 2026
If molar conductance at infinite dilution for $CH_3COO^-$ and $H^+$ ions are $50 \text{ S cm}^2 \text{mol}^{-1}$ and $350 \text{ S cm}^2 \text{mol}^{-1}$ respectively, and the molar conductivity of $5 \times 10^{-2} \text{ M}$ $CH_3COOH$ is $20 \text{ S cm}^2 \text{mol}^{-1}$, what is the hydrogen ion concentration in $\text{mol/dm}^3$ of $CH_3COOH$?
A
$5 \times 10^{-2}$
B
$5 \times 10^{-3}$
C
$2.5 \times 10^{-3}$
D
$2.5 \times 10^{-4}$

Solution

(C) Step $1$: Calculate the molar conductivity at infinite dilution $(\Lambda_m^0)$ for $CH_3COOH$ using Kohlrausch's law:
$\Lambda_m^0(CH_3COOH) = \lambda^0(CH_3COO^-) + \lambda^0(H^+) = 50 + 350 = 400 \text{ S cm}^2 \text{mol}^{-1}$.
Step $2$: Calculate the degree of dissociation $(\alpha)$:
$\alpha = \frac{\Lambda_m^c}{\Lambda_m^0} = \frac{20}{400} = 0.05$.
Step $3$: Calculate the hydrogen ion concentration $[H^+]$:
$[H^+] = C \times \alpha = (5 \times 10^{-2} \text{ M}) \times 0.05 = 2.5 \times 10^{-3} \text{ mol/dm}^3$.
229
ChemistryEasyMCQMHT CET · 2026
Which of the following statements is true about the voltaic cell?
A
It converts chemical energy into electrical energy.
B
It converts electrical energy into chemical energy.
C
The anode of voltaic cells is positive.
D
The cathode of voltaic cell is negative.

Solution

(A) Step $1$: $A$ voltaic cell (or galvanic cell) is an electrochemical cell that derives electrical energy from spontaneous redox reactions occurring within the cell.
Step $2$: In a voltaic cell, chemical energy is converted into electrical energy.
Step $3$: By convention, the anode is the electrode where oxidation occurs (negative terminal) and the cathode is the electrode where reduction occurs (positive terminal).
Step $4$: Therefore, option $A$ is the correct statement.
230
ChemistryMediumMCQMHT CET · 2026
Which of the following statements regarding a mercury battery is $NOT$ true?
A
It is a primary dry cell.
B
It consists of a $Zn$ anode amalgamated with mercury.
C
The electrolyte is strongly acidic.
D
In this, $Hg$ is obtained by the reduction of $HgO$.

Solution

(C) Step $1$: $A$ mercury battery is a primary cell that uses a $Zn$ anode and a $HgO$ cathode.
Step $2$: The electrolyte used is a paste of $KOH$ and $ZnO$, which is strongly alkaline (basic), not acidic.
Step $3$: The cell reaction at the cathode is $HgO(s) + H_2O(l) + 2e^- \rightarrow Hg(l) + 2OH^-(aq)$, where $HgO$ is reduced to $Hg$.
Step $4$: Since the electrolyte is basic, the statement that it is strongly acidic is false.
231
ChemistryEasyMCQMHT CET · 2026
Which of the following is used as an electrolyte in a dry cell?
A
Potassium hydroxide
B
Sulphuric acid
C
Ammonium chloride and zinc chloride
D
Manganese dioxide

Solution

(C) In a dry cell (Leclanché cell), the electrolyte is a moist paste of $NH_4Cl$ (ammonium chloride) and $ZnCl_2$ (zinc chloride). The $MnO_2$ (manganese dioxide) acts as the depolarizer, while the zinc container acts as the anode and a graphite rod acts as the cathode.
232
ChemistryMediumMCQMHT CET · 2026
What happens during the discharge of a lead storage battery?
A
$SO_2$ is evolved
B
$Pb$ is formed
C
$H_2SO_4$ is consumed
D
$PbSO_4$ is consumed

Solution

(C) During the discharge of a lead storage battery, the following chemical reactions occur:
At anode: $Pb(s) + SO_4^{2-}(aq) \rightarrow PbSO_4(s) + 2e^-$
At cathode: $PbO_2(s) + SO_4^{2-}(aq) + 4H^+(aq) + 2e^- \rightarrow PbSO_4(s) + 2H_2O(l)$
Overall reaction: $Pb(s) + PbO_2(s) + 2H_2SO_4(aq) \rightarrow 2PbSO_4(s) + 2H_2O(l)$
From the overall reaction, it is clear that $H_2SO_4$ is consumed as the battery discharges.
233
ChemistryEasyMCQMHT CET · 2026
Which of the following hot aqueous solutions is used to dip carbon rods of $H_2 - O_2$ fuel cell?
A
$KCl$
B
$KOH$
C
$H_2SO_4$
D
$NH_4Cl$

Solution

(B) In a $H_2 - O_2$ fuel cell, the electrodes are made of porous carbon rods impregnated with a catalyst (like $Pt$ or $Pd$).
These electrodes are dipped into a hot aqueous solution of $KOH$ or $NaOH$, which acts as the electrolyte.
Therefore, the correct option is $KOH$.
234
ChemistryMediumMCQMHT CET · 2026
What is the change in oxidation number of $Pb$ at the positive electrode of a lead accumulator acting as a galvanic cell?
A
increases by $1$
B
decreases by $1$
C
increases by $2$
D
decreases by $2$

Solution

(D) In a lead accumulator acting as a galvanic cell, the positive electrode is the cathode.
The reduction reaction at the cathode is: $PbO_2 + 4H^+ + SO_4^{2-} + 2e^- \rightarrow PbSO_4 + 2H_2O$.
In $PbO_2$, the oxidation state of $Pb$ is $+4$.
In $PbSO_4$, the oxidation state of $Pb$ is $+2$.
Change in oxidation number = $+2 - (+4) = -2$.
Thus, the oxidation number decreases by $2$.
235
ChemistryMediumMCQMHT CET · 2026
Which of the following reactions occurs at the cathode during the recharging of a lead storage battery?
A
$PbSO_4(s) + 2H_2O(\ell) \rightarrow PbO_2(s) + SO_4^{2-}(aq.) + 4H^+(aq.) + 2e^-$
B
$PbO_2(s) + 4H^+(aq.) + SO_4^{2-}(aq.) + 2e^- \rightarrow PbSO_4(s) + 2H_2O(\ell)$
C
$Pb(s) + SO_4^{2-}(aq.) \rightarrow PbSO_4(s) + 2e^-$
D
$PbSO_4(s) + 2e^- \rightarrow Pb(s) + SO_4^{2-}(aq.)$

Solution

(D) During the recharging of a lead storage battery, the cell acts as an electrolytic cell.
At the cathode (negative electrode during recharging), the reduction reaction is: $PbSO_4(s) + 2e^- \rightarrow Pb(s) + SO_4^{2-}(aq.)$.
At the anode (positive electrode during recharging), the oxidation reaction is: $PbSO_4(s) + 2H_2O(\ell) \rightarrow PbO_2(s) + SO_4^{2-}(aq.) + 4H^+(aq.) + 2e^-$.
Therefore, the reaction occurring at the cathode is $PbSO_4(s) + 2e^- \rightarrow Pb(s) + SO_4^{2-}(aq.)$.
236
ChemistryMediumMCQMHT CET · 2026
Identify the function of a salt bridge in an electrochemical cell.
A
To act as a cathode
B
To act as an anode
C
To connect two half-cells and maintain electrical neutrality
D
To measure the electrode potential

Solution

(C) $1$. $A$ salt bridge is a $U$-shaped tube containing an electrolyte (like $KCl$ or $KNO_3$) in a gel.
$2$. Its primary functions are to connect the two half-cells internally and to maintain electrical neutrality in the solutions of both half-cells by allowing the migration of ions.
$3$. It prevents the accumulation of charge, which would otherwise stop the flow of electrons and the reaction.
$4$. Therefore, option $C$ is the correct function.
237
ChemistryMediumMCQMHT CET · 2026
Which of the following statements is correct regarding the electrolysis of molten $NaCl$?
A
Pale green $Cl_2$ gas is released at the anode
B
Molten silvery-white sodium metal is deposited at the cathode
C
Decomposition of $NaCl$ into $Na$ metal and $Cl_2$ gas
D
Both options $A$ and $B$

Solution

(D) $1$. During the electrolysis of molten $NaCl$, the dissociation reaction is: $2NaCl(l) \rightarrow 2Na^+(l) + 2Cl^-(l)$.
$2$. At the anode (oxidation): $2Cl^-(l) \rightarrow Cl_2(g) + 2e^-$. Pale green $Cl_2$ gas is evolved.
$3$. At the cathode (reduction): $2Na^+(l) + 2e^- \rightarrow 2Na(l)$. Molten silvery-white sodium metal is deposited.
$4$. Since both statements $A$ and $B$ are correct, the correct option is $D$.
238
ChemistryDifficultMCQMHT CET · 2026
Match List $I$ with List $II$.
List $I$ (Conversion)List $II$ (Number of Faraday required)
$A$. $1 \text{ mol of } H_2O \text{ to } O_2$$I$. $3F$
$B$. $1 \text{ mol of } MnO_4^- \text{ to } Mn^{2+}$$II$. $2F$
$C$. $1.5 \text{ mol of } Ca \text{ from molten } CaCl_2$$III$. $1F$
$D$. $1 \text{ mol of } FeO \text{ to } Fe_2O_3$$IV$. $5F$
Choose the correct answer from the options given below:
A
$A-II, B-IV, C-I, D-III$
B
$A-III, B-IV, C-I, D-II$
C
$A-II, B-III, C-I, D-IV$
D
$A-III, B-IV, C-II, D-I$

Solution

(A) . For $H_2O \rightarrow H_2 + \frac{1}{2}O_2$, the reaction is $H_2O \rightarrow \frac{1}{2}O_2 + 2H^+ + 2e^-$. Thus, $2F$ are required.
$B$. For $MnO_4^- \rightarrow Mn^{2+}$, the change in oxidation state of $Mn$ is from $+7$ to $+2$. The reaction is $MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$. Thus, $5F$ are required.
$C$. For $Ca^{2+} + 2e^- \rightarrow Ca$, $1 \text{ mol}$ of $Ca$ requires $2F$. So, $1.5 \text{ mol}$ of $Ca$ requires $1.5 \times 2 = 3F$.
$D$. For $FeO \rightarrow \frac{1}{2}Fe_2O_3$, the reaction is $Fe^{2+} \rightarrow Fe^{3+} + e^-$. Thus, $1F$ is required.
Matching: $A-II, B-IV, C-I, D-III$.
239
ChemistryDifficultMCQMHT CET · 2026
The standard electrode potential of $Cu^{2+}/Cu$ is $0.34 \text{ V}$ at $298 \text{ K}$. Calculate its electrode potential at the same temperature when the $Cu^{2+}$ ion concentration is $0.1 \text{ M}$. (in $\text{ V}$)
A
$0.64$
B
$0.34$
C
$0.31$
D
$0.37$

Solution

(C) The Nernst equation for the electrode reaction $Cu^{2+} + 2e^- \rightarrow Cu(s)$ is:
$E_{Cu^{2+}/Cu} = E^0_{Cu^{2+}/Cu} - \frac{0.0591}{n} \log \frac{1}{[Cu^{2+}]}$
Here, $n = 2$ and $[Cu^{2+}] = 0.1 \text{ M} = 10^{-1} \text{ M}$.
Substituting the values:
$E = 0.34 - \frac{0.0591}{2} \log \frac{1}{10^{-1}}$
$E = 0.34 - 0.02955 \log(10)$
Since $\log(10) = 1$, we get:
$E = 0.34 - 0.02955 = 0.31045 \text{ V} \approx 0.31 \text{ V}$.
240
ChemistryDifficultMCQMHT CET · 2026
Identify which of the following cell reactions is spontaneous under standard state conditions.
A
$Ca(s) + Cd^{2+}(aq) \rightarrow Ca^{2+}(aq) + Cd(s)$ $[E^0_{Ca^{2+}/Ca} = -2.866 \text{ V}, E^0_{Cd^{2+}/Cd} = -0.403 \text{ V}]$
B
$2Br^-(aq) + Sn^{2+}(aq) \rightarrow Br_2(l) + Sn(s)$ $[E^0_{Br_2/Br^-} = 1.08 \text{ V}, E^0_{Sn^{2+}/Sn} = -0.136 \text{ V}]$
C
$2Ag(s) + Ni^{2+}(aq) \rightarrow 2Ag^+(aq) + Ni(s)$ $[E^0_{Ag^+/Ag} = 0.799 \text{ V}, E^0_{Ni^{2+}/Ni} = -0.257 \text{ V}]$
D
$2Au(s) + Zn^{2+}(aq) \rightarrow 2Au^+(aq) + Zn(s)$ $[E^0_{Au^+/Au} = 1.68 \text{ V}, E^0_{Zn^{2+}/Zn} = -0.763 \text{ V}]$

Solution

(A) reaction is spontaneous if $E^0_{cell} > 0$. $E^0_{cell} = E^0_{cathode} - E^0_{anode}$.
For $(A)$: $E^0_{cell} = (-0.403) - (-2.866) = +2.463 \text{ V}$. Since $E^0_{cell} > 0$, it is spontaneous.
For $(B)$: $E^0_{cell} = (-0.136) - (1.08) = -1.216 \text{ V}$. Non-spontaneous.
For $(C)$: $E^0_{cell} = (-0.257) - (0.799) = -1.056 \text{ V}$. Non-spontaneous.
For $(D)$: $E^0_{cell} = (-0.763) - (1.68) = -2.443 \text{ V}$. Non-spontaneous.
241
ChemistryEasyMCQMHT CET · 2026
Which of the following statements is correct regarding the cathode of an electrochemical cell?
A
Oxidation occurs at the cathode.
B
Reduction occurs at the cathode.
C
It is usually denoted by a negative sign.
D
It is usually made up of non-conducting material.

Solution

(B) In an electrochemical cell, the cathode is the electrode where reduction (gain of electrons) takes place.
In a galvanic cell, the cathode is positive, while in an electrolytic cell, the cathode is negative.
Therefore, the statement 'Reduction occurs at the cathode' is always correct.
242
ChemistryMediumMCQMHT CET · 2026
Which of the following reactions is possible at the anode?
A
$F_2 + 2e^- \rightarrow 2F^-$
B
$2H^+ + \frac{1}{2} O_2 + 2e^- \rightarrow H_2O$
C
$Fe^{2+} \rightarrow Fe^{3+} + 1e^-$
D
$Cu^{2+} + 2e^- \rightarrow Cu(s)$

Solution

(C) $1$. The anode is the electrode where oxidation occurs.
$2$. Oxidation is defined as the loss of electrons.
$3$. In option $(A)$, $F_2$ gains electrons (reduction).
$4$. In option $(B)$, $H^+$ and $O_2$ gain electrons (reduction).
$5$. In option $(C)$, $Fe^{2+}$ loses an electron to form $Fe^{3+}$, which is an oxidation process.
$6$. In option $(D)$, $Cu^{2+}$ gains electrons (reduction).
$7$. Therefore, the reaction in option $(C)$ is the only one that represents oxidation and can occur at the anode.
243
ChemistryDifficultMCQMHT CET · 2026
The $E^0_{cell}$ of the cell $Al(s)|Al^{3+}(1M)||Pb^{2+}(1M)|Pb(s)$ is $1.5 \text{ V}$. If $E^0_{Pb^{2+}/Pb}$ is $-0.14 \text{ V}$, then $E^0_{Al^{3+}/Al}$ will be: (in $\text{ V}$)
A
$1.64$
B
$-1.64$
C
$1.36$
D
$-1.36$

Solution

(B) The standard cell potential is given by the formula: $E^0_{cell} = E^0_{cathode} - E^0_{anode}$.
Here, the cathode is $Pb^{2+}/Pb$ and the anode is $Al^{3+}/Al$.
Given: $E^0_{cell} = 1.5 \text{ V}$ and $E^0_{cathode} = -0.14 \text{ V}$.
Substituting the values: $1.5 \text{ V} = -0.14 \text{ V} - E^0_{anode}$.
Rearranging the equation: $E^0_{anode} = -0.14 \text{ V} - 1.5 \text{ V}$.
Therefore, $E^0_{Al^{3+}/Al} = -1.64 \text{ V}$.
244
ChemistryDifficultMCQMHT CET · 2026
Cells $A$ and $B$ contain aqueous solutions of ferrous chloride $(FeCl_2)$ and ferric chloride $(FeCl_3)$ respectively. If the same quantity of electricity is passed through both cells, what is the ratio of the mass of iron deposited in cell $A$ to that in cell $B$?
A
$1:1$
B
$2:1$
C
$3:1$
D
$3:2$

Solution

(D) According to Faraday's second law of electrolysis, the mass $(m)$ of a substance deposited is given by $m = \frac{M \cdot Q}{n \cdot F}$, where $M$ is the molar mass, $Q$ is the quantity of electricity, $n$ is the valency factor, and $F$ is Faraday's constant.
Since $Q$ and $F$ are constant, $m \propto \frac{M}{n}$.
For cell $A$ $(FeCl_2)$, the iron is in the $Fe^{2+}$ state, so $n_A = 2$.
For cell $B$ $(FeCl_3)$, the iron is in the $Fe^{3+}$ state, so $n_B = 3$.
The ratio of the mass of iron deposited is $\frac{m_A}{m_B} = \frac{M/n_A}{M/n_B} = \frac{n_B}{n_A} = \frac{3}{2} = 3:2$.
245
ChemistryEasyMCQMHT CET · 2026
Identify the reaction from the following that corresponds to the standard electrode potential of the $Cu^{+2}/Cu$ electrode being $0.34 \text{ V}$ with respect to the $SHE$?
A
$Cu \rightarrow Cu^{+2} + 2e^-$
B
$Cu^{+2} + 2e^- \rightarrow Cu$
C
$Cu^+ \rightarrow Cu^{+2} + e^-$
D
$Cu^{+3} \rightarrow Cu^{+2} + e^-$

Solution

(B) The standard electrode potential $E^\circ$ is defined for the reduction half-reaction.
For the $Cu^{+2}/Cu$ electrode, the reduction reaction is the gain of electrons by the copper ion to form metallic copper.
The reaction is: $Cu^{+2}(aq) + 2e^- \rightarrow Cu(s)$.
Thus, option $B$ represents the correct reduction reaction.
246
ChemistryMediumMCQMHT CET · 2026
Which of the following reactions takes place at the anode during the electrolysis of molten $NaCl$?
A
$Na^+(l) + e^- \rightarrow Na(l)$
B
$Na(s) \rightarrow Na^+(l) + e^-$
C
$Cl_2(g) + 2e^- \rightarrow 2Cl^-(l)$
D
$2Cl^-(l) \rightarrow Cl_2(g) + 2e^-$

Solution

(D) $1$. During the electrolysis of molten $NaCl$, the electrolyte dissociates into $Na^+$ and $Cl^-$ ions.
$2$. The anode is the positively charged electrode, which attracts negatively charged ions (anions).
$3$. The chloride ions $(Cl^-)$ migrate to the anode.
$4$. At the anode, oxidation occurs, where $Cl^-$ ions lose electrons to form chlorine gas $(Cl_2)$: $2Cl^-(l) \rightarrow Cl_2(g) + 2e^-$.
$5$. Therefore, option $D$ is the correct reaction.
247
ChemistryDifficultMCQMHT CET · 2026
What mass of silver (Atomic mass = $108 \text{ g/mol}$) is deposited by a quantity of electricity that displaces $5600 \text{ mL}$ of $O_2$ gas at $STP$ (in $\text{ g}$)?
A
$5.4$
B
$10.8$
C
$54.0$
D
$108.0$

Solution

(D) Step $1$: Calculate moles of $O_2$ gas at $STP$. Moles = $5600 \text{ mL} / 22400 \text{ mL/mol} = 0.25 \text{ mol}$.
Step $2$: Calculate equivalents of $O_2$. The reaction is $2H_2O \rightarrow O_2 + 4H^+ + 4e^-$. The $n$-factor for $O_2$ is $4$. Equivalents = $0.25 \times 4 = 1$.
Step $3$: According to Faraday's law, equivalents of $Ag$ deposited = equivalents of $O_2$ displaced = $1$.
Step $4$: Mass of $Ag$ = Equivalents $\times$ Equivalent mass = $1 \times 108 \text{ g/mol} = 108 \text{ g}$.
248
ChemistryDifficultMCQMHT CET · 2026
If the $emf$ of the cell $Cu(s) | Cu^{2+}(1 \text{ M}) || Ag^+(1 \text{ M}) | Ag(s)$ is $0.463 \text{ V}$ at $25^{\circ} \text{C}$ and the standard electrode potential of the $Cu$ electrode is $0.337 \text{ V}$, find the standard electrode potential of the $Ag$ electrode. (in $\text{ V}$)
A
$0.128$
B
$-0.128$
C
$0.8$
D
$-0.8$

Solution

(C) The standard cell potential $E^0_{cell}$ is given by the difference between the standard reduction potentials of the cathode and the anode:
$E^0_{cell} = E^0_{cathode} - E^0_{anode}$
Here, the cathode is $Ag$ and the anode is $Cu$, so:
$E^0_{cell} = E^0_{Ag^+/Ag} - E^0_{Cu^{2+}/Cu}$
Given $E^0_{cell} = 0.463 \text{ V}$ and $E^0_{Cu^{2+}/Cu} = 0.337 \text{ V}$:
$0.463 \text{ V} = E^0_{Ag^+/Ag} - 0.337 \text{ V}$
$E^0_{Ag^+/Ag} = 0.463 \text{ V} + 0.337 \text{ V} = 0.800 \text{ V}$
Thus, the standard potential of the $Ag$ electrode is $0.8 \text{ V}$.
249
ChemistryDifficultMCQMHT CET · 2026
If standard reduction potentials $(E^0)$ of $(Al^{+3}(aq)|Al(s))$, $(Fe^{+2}(aq)|Fe(s))$, $(Cu^{+2}(aq)|Cu(s))$ and $(Ag^{+1}(aq)|Ag(s))$ are $-1.66 \text{ V}$, $-0.44 \text{ V}$, $+0.34 \text{ V}$ and $+0.79 \text{ V}$ respectively, which of the following reactions is non-spontaneous?
A
$2Ag(s) + Fe^{+2}(aq) \rightarrow 2Ag^{+}(aq) + Fe(s)$
B
$2Al(s) + 3Cu^{+2}(aq) \rightarrow 2Al^{+3}(aq) + 3Cu(s)$
C
$Fe(s) + Cu^{+2}(aq) \rightarrow Fe^{+2}(aq) + Cu(s)$
D
$2Al(s) + 3Fe^{+2}(aq) \rightarrow 2Al^{+3}(aq) + 3Fe(s)$

Solution

(A) reaction is non-spontaneous if the standard cell potential $E^0_{cell} < 0$.
For option $A$: $E^0_{cell} = E^0_{cathode} - E^0_{anode} = E^0_{Fe^{+2}/Fe} - E^0_{Ag^{+}/Ag} = -0.44 - 0.79 = -1.23 \text{ V}$. Since $E^0_{cell} < 0$, this reaction is non-spontaneous.
For option $B$: $E^0_{cell} = 0.34 - (-1.66) = 2.00 \text{ V} > 0$ (Spontaneous).
For option $C$: $E^0_{cell} = 0.34 - (-0.44) = 0.78 \text{ V} > 0$ (Spontaneous).
For option $D$: $E^0_{cell} = -0.44 - (-1.66) = 1.22 \text{ V} > 0$ (Spontaneous).
250
ChemistryMediumMCQMHT CET · 2026
Which of the following net cell reactions occurs in a galvanic cell containing a cadmium electrode and a standard hydrogen electrode? Given: $E^0(Cd^{2+}(aq)|Cd(s)) = -0.403 \text{ V}$.
A
$H_2(g) + Cd^{2+}(aq) \rightarrow 2H^+(aq) + Cd(s)$
B
$Cd(s) + 2H^+(aq) \rightarrow Cd^{2+}(aq) + H_2(g)$
C
$2H_2(g) + Cd^{2+}(aq) \rightarrow 4H^+(aq) + Cd(s)$
D
$2Cd(s) + 2H^+(aq) \rightarrow 2Cd^{2+}(aq) + H_2(g)$

Solution

(B) Step $1$: Identify the standard electrode potentials. For the standard hydrogen electrode $(SHE)$, $E^0(H^+|H_2) = 0.00 \text{ V}$. For the cadmium electrode, $E^0(Cd^{2+}|Cd) = -0.403 \text{ V}$.
Step $2$: Determine the anode and cathode. Since $E^0(Cd^{2+}|Cd) < E^0(H^+|H_2)$, the cadmium electrode acts as the anode (oxidation) and the hydrogen electrode acts as the cathode (reduction).
Step $3$: Write the half-reactions. Anode: $Cd(s) \rightarrow Cd^{2+}(aq) + 2e^-$. Cathode: $2H^+(aq) + 2e^- \rightarrow H_2(g)$.
Step $4$: Combine the half-reactions to get the net cell reaction: $Cd(s) + 2H^+(aq) \rightarrow Cd^{2+}(aq) + H_2(g)$.

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