How much heat change in $kJ$ will occur when $233.0 \, g$ of calcium oxide reacts with sufficient carbon to produce $CaC_2$? The reaction is: $CaO_{(s)} + 3C_{(s)} \to CaC_{2(s)} + CO_{(g)}$; $\Delta H^o = 464.8 \, kJ/mol$.

$A$ mixture of dihydrogen and dioxygen at $1 \ bar$ pressure contains $20 \%$ by weight of dihydrogen. Calculate the partial pressure of dihydrogen. (in $bar$)

How many grams of $3-$hydroxypropanal $(MW=74)$ must be dehydrated to produce $7.8 \ g$ of acrolein $(MW=56)$ $(C_3H_4O)$ if the percentage yield is $64\%$? (Round off to the nearest integer).
[Given: Atomic masses: $C = 12.0 \ u, H = 1.0 \ u, O = 16.0 \ u$]

Match the following and select the correct option:

List-$I$	List-$II$ (At $STP$)
$(A)$ $10 \ g \ CaCO_3 \xrightarrow{\Delta} \text{decomposition}$	$(i)$ $0.224 \ L \ CO_2$
$(B)$ $1.06 \ g \ Na_2CO_3 \xrightarrow{\text{Excess } HCl}$	$(ii)$ $4.48 \ L \ CO_2$
$(C)$ $2.4 \ g \ C \xrightarrow{\text{Excess } O_2} \text{combustion}$	$(iii)$ $0.448 \ L \ CO_2$
$(D)$ $0.56 \ g \ CO \xrightarrow{\text{Excess } O_2} \text{combustion}$	$(iv)$ $2.24 \ L \ CO_2$
	$(v)$ $22.4 \ L \ CO_2$

Two elements $A$ and $B$ form $0.15 \ mol$ of $A_2 B$ and $AB_3$ type compounds. If $0.15 \ mol$ of both $A_2 B$ and $AB_3$ weigh equally,then the atomic weight of $A$ is $...$ times the atomic weight of $B$.

To neutralise $20 \, mL$ of $M/10$ sodium hydroxide,the volume of $M/20$ hydrochloric acid required is .............. $mL$