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 $Ba = 137$,$C = 12$,$O = 16$)

$10 \text{ g}$ of a mixture of $BaO$ and $CaO$ requires $100 \text{ cm}^3$ of $2.5 \text{ M } HCl$ to react completely. The percentage of calcium oxide in the mixture is approximately (Given: molar mass of $BaO = 153 \text{ g/mol}$,$CaO = 56 \text{ g/mol}$).

What is the volume in $litres$ of the gas produced at $NTP$ by the reaction of $100 \ g$ of $CaC_2$ with water?
$CaC_2 + 2H_2O \rightarrow Ca(OH)_2 + C_2H_2$

One mole of fluorine is reacted with two moles of hot concentrated $KOH$. The products formed are $KF, H_2O$ and $O_2$. The molar ratio of $KF, H_2O$ and $O_2$,respectively is

$12 \ g$ of $Mg$ (atomic mass $24$) will react completely with acid to give:

For the reaction $Fe_{2}O_{3} + 3 CO \longrightarrow 2 Fe + 3 CO_{2}$,the volume of carbon monoxide required to reduce one mole of ferric oxide is (in $dm^{3}$)