One mole of nitrogen gas on reaction with $3.01 \times 10^{23}$ molecules of hydrogen gas produces

What will be the volume of the mixture after the reaction? $litre$
$NH_3(4 \ litre) + HCl(1.5 \ litre) \to NH_4Cl(s)$

$A$ reaction gas mixture contains $50 \%$,$30 \%$,and $20 \%$ of $A$,$B$,and $C$ by volume,respectively. The mixture undergoes the following reactions:
$1. A + 2B \rightarrow P_1$
$2. 4P_1 + 3C \rightarrow P_2$
$P_1$ and $P_2$ are two products of the reactions. Choose the correct answer if the reaction completes.

When $20 \ g$ of $CaCO_3$ is treated with $20 \ g$ of $HCl$,the mass of $CO_2$ formed would be: (in $g$)

According to the reaction $2A + B \to C$,$8 \ mol$ of $A$ and $5 \ mol$ of $B$ will produce how many moles of $C$?

Moles of conc. $HNO_3$ required to oxidise one mole of sulphur is :
$S + 6HNO_3 \rightarrow H_2SO_4 + 6NO_2 + 2H_2O$