Find the resulting $pH$ of the mixture of $200 \ mL$ of $HCl$ $(pH = 2)$ and $300 \ mL$ of $NaOH$ $(pH = 12.0)$.

What is the $[OH^{-}]$ in the final solution prepared by mixing $20.0 \ mL$ of $0.050 \ M \ HCl$ with $30.0 \ mL$ of $0.10 \ M \ Ba(OH)_2$? $...... \ M$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$BaCO_3 \downarrow + 2HCl \longrightarrow BaCl_2 + CO_2 \uparrow + H_2O$

Hydrogen ion concentration of an aqueous solution is $1 \times 10^{-4} \ M$. The solution is diluted with an equal volume of water. The hydroxyl ion concentration of the resultant solution in terms of $mol \ dm^{-3}$ is

The solubility of $AgCl$ is $4 \times 10^{-6} \ M$. Find its $K_{sp}$. Also,find its new solubility in the presence of $2 \times 10^{-3} \ M \ CaCl_2$.

When $100 \ mL$ of $1.0 \ M \ HCl$ was mixed with $100 \ mL$ of $1.0 \ M \ NaOH$ in an insulated beaker at constant pressure,a temperature increase of $5.7^{\circ} C$ was measured for the beaker and its contents (Expt. $1$). Because the enthalpy of neutralization of a strong acid with a strong base is a constant $\left(-57.0 \ kJ \ mol ^{-1}\right)$,this experiment could be used to measure the calorimeter constant. In a second experiment (Expt. $2$),$100 \ mL$ of $2.0 \ M$ acetic acid $\left(K_a=2.0 \times 10^{-5}\right)$ was mixed with $100 \ mL$ of $1.0 \ M \ NaOH$ (under identical conditions to Expt. $1$) where a temperature rise of $5.6^{\circ} C$ was measured.
(Consider heat capacity of all solutions as $4.2 \ J \ g ^{-1} K ^{-1}$ and density of all solutions as $1.0 \ g \ mL ^{-1}$)
$1.$ Enthalpy of dissociation (in $kJ \ mol ^{-1}$) of acetic acid obtained from the Expt. $2$ is
$(A) \ 1.0 \ (B) \ 10.0 \ (C) \ 24.5 \ (D) \ 51.4$
$2.$ The $pH$ of the solution after Expt. $2$ is
$(A) \ 2.8 \ (B) \ 4.7 \ (C) \ 5.0 \ (D) \ 7.0$
Give the answer for question $1$ and $2.$