JEE Main 2020 — Some Basic Concepts of Chemistry Question with Solution

 Mass ratio of $\mathrm{C} : \mathrm{H} \mathrm{is} 4 : 1\Rightarrow 12 : 3$

& $\mathrm{C} : \mathrm{O} \mathrm{is} 3 : 4 \Rightarrow 12 : 16$

so $$\begin{gathered} \mathrm{mass} \mathrm{mole} \mathrm{mole} \mathrm{ratio} \\ \mathrm{C} 12 1 1 \\ \mathrm{H} 3 3 3 \\ \mathrm{O} 16 1 1 \end{gathered}$$

Empirical formula $\Rightarrow$${\mathrm{CH}}_3\mathrm{O}$

as compound is saturated acyclic so molecular formula is ${\mathrm{C}}_2{\mathrm{H}}_6{\mathrm{O}}_2$.

${\mathrm{C}}_2{\mathrm{H}}_6{\mathrm{O}}_2+\frac{5}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)⟶2{\mathrm{CO}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$
 $2$mole       $5$mole

so required moles of ${\mathrm{O}}_2$is $\Rightarrow 5$