Calculate the weight of $CaO$ formed in quintals when $10 \ g$ of $CaCO_3$ is heated with $4.4 \ g$ of $CO_2$.

$CaCO_3 + 2HCl \to CaCl_2 + CO_2 + H_2O$ ; In this chemical reaction,what will be the amount of calcium chloride formed when $10 \ g$ of calcium carbonate and $400 \ mL$ of $0.25 \ M$ $HCl$ are used? (Atomic masses: $Ca=40, C=12, O=16, H=1, Cl=35.5$)

What are $x$ and $y$ in the following reaction?
$x Pb_3O_4 \rightarrow y PbO + O_2$

Combustion of $50 \ mL$ methane is carried out with $150 \ mL$ of air containing $21 \%$ oxygen by volume. What will be the total volume of the gaseous mixture after the reaction? (Assume water is in the gaseous state and air contains $79 \%$ nitrogen by volume).
$CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(g)}$

For a given unbalanced reaction,$MnO_2 + HCl \rightarrow MnCl_2 + H_2O + Cl_2$,which is the limiting reagent if the initial amount for each reactant is $100 \ g$? [Molar masses: $MnO_2 = 86.9 \ g/mol$; $HCl = 36.5 \ g/mol$]

The reactant which is entirely consumed in a reaction is known as the limiting reagent. In the reaction $2A + 4B \to 3C + 4D$,when $5 \ mol$ of $A$ react with $6 \ mol$ of $B$,then:
$(i)$ Which is the limiting reagent?
$(ii)$ Calculate the amount of $C$ formed.