Passage:

            Calculations based on mole – mole relationship:

            In some calculations, if number of moles of reactants are given then the number of moles of

            products are calculated, if number of moles of products are given, then the number of moles of

            reactants are calculated.

            Ex:  ${\text{CaCO}}_{3\left(\text{s}\right)}\to {\text{CaO}}_{\left(\text{s}\right)}+{\text{CO}}_{2\left(\text{g}\right)}$

Q. The balanced chemical equation for the reaction of Acetylene produced from ${\text{CaC}}_2$ and ${\text{H}}_{\text{2}}\text{O}$ is shown below ${\text{CaC}}_{\text{2}}+{\text{2H}}_{\text{2}}\text{O}\to {\text{C}}_{\text{2}}{\text{H}}_{\text{2}}+\text{Ca}{\left(\text{OH}\right)}_2$   

If 4 moles of is ${\text{H}}_{\text{2}}\text{O}$ available, then the no. of moles of ${\text{CaC}}_{\text{2}}$ needed to complete the reaction