What is the volume of $CO_2$ in liters produced at $STP$ by the complete decomposition of $9.85 \ g$ of $BaCO_3$? (Atomic mass of $Ba = 137$,$C = 12$,$O = 16$)

$A$ gas weighing $2.4 \ g$ has a vapor density of $11.2$. What is its volume in $L$ at $STP$?

What is the volume (in litres) of oxygen at $STP$ required for complete combustion of $32 \,g$ of $CH_4$? (Molecular weight of $CH_4$ is $16$)

At $STP$,the volume of $4.4 \, g$ of an unknown gas is $2.24 \, L$. Which of the following is this gas?

What is the volume occupied by $2.5 \ mol$ of ammonia gas at $\text{STP}$ (in $dm^3$)?

$0.01\, M\, KMnO_{4}$ solution was added to $20.0\, mL$ of $0.05\, M$ Mohr's salt solution through a burette. The initial reading of $50\, mL$ burette is zero. The volume of $KMnO_{4}$ solution left in the burette after the end point is $.....\, mL$. (nearest integer)