When a $1.0 \, g$ mixture of $NaHCO_3$ and $Na_2CO_3$ is heated at $150^{\circ}C$,$112.0 \, mL$ of $CO_2$ is produced at $STP$. Calculate the percentage of $Na_2CO_3$ in the mixture. $(Na = 23, C = 12, O = 16)$

What volume (in $mL$) of gaseous $NH_3$ at $N.T.P.$ is required to be passed into $30 \, mL$ of $1 \, N \, H_2SO_4$ solution to reduce the acid strength of this solution to $0.2 \, N$?

What is the volume (in $mL$) of $20$ vol $H_2O_2$ required to completely react with $500 \ mL$ of $0.02 \ M$ acidified $KMnO_4$ solution?

The amount of carbon dioxide evolved upon complete combustion of $116 \ g$ of $n$-butane is
(Given : atomic mass in amu $H = 1, C = 12$ and $O = 16$) (in $g$)

Hydrochloric acid solutions $A$ and $B$ have concentrations of $0.5 \,N$ and $0.1 \,N$ respectively. The volumes of solutions $A$ and $B$ required to make $2 \,L$ of $0.2 \,N$ hydrochloric acid are:

$20 \ g$ of iron pyrite,$FeS_2$,is roasted completely and the $SO_2$ gas produced is absorbed completely in $400 \ mL$ of $NaOH$ solution. If only $50\%$ of the $NaOH$ is used in the reaction,what was the molarity of the $NaOH$ solution?