Chemistry - Mole Concept Question with Solution | TestHub

Suppose the molecular formula of hydrocarbon =${\mathrm{C}}_{\mathrm{x}}{\mathrm{H}}_{\mathrm{y}}$
${\text{C}}_{\text{x}}{\text{H}}_{\text{y}}\left(\text{g}\right)+\left(\text{x}+\frac{\text{y}}{4}\right){\text{O}}_{\text{2}}\left(\text{g}\right)\to {\text{xCO}}_2\left(\text{g}\right)+\frac{\text{y}}{2}{\text{H}}_2\text{O}\left(\mathcal{l}\right)$
Volume of hydrocarbon = 10 ml
Decreases in volume = 10 + 80 – 70 = 20 ml
Volume of$\mathrm{C}{\mathrm{O}}_2=70-50=20$ml
$\mathrm{x}=\frac{20}{10}=2$
${\text{V}}_{\text{O}}{}_{{}_2}\left(\text{left}\right)=50\text{ml}$
${\text{V}}_{\text{O}}{}_{{}_2}\left(\text{Consumed}\right)=80-50=30\text{ml}$
${\text{V}}_{\text{O}}{}_{{}_2}\left(\text{Consumed}\right)={\text{V}}_{\text{H}\text{.C}\text{.}}\times \left(\text{x}+\frac{\text{y}}{4}\right)$
$30=10\times \left(2+\frac{\text{y}}{4}\right)$
$\text{y}=\left(3-2\right)\times 4=4$
Molecular formula is${\mathrm{C}}_2{\mathrm{H}}_4$.