$C: O=3: 4$

Mass ratio

$C : H : O =12: 3: 16$

Mole ratio

$C : H : O =1: 3: 1$

Empirical formula $= CH _{3} O$

Molecular formula $= C _{2} H _{6} O _{2}$

(saturated acyclic organic compound)

$C _{2} H _{6} O _{2}+\frac{5}{2} O _{2} \longrightarrow 2 CO _{2}+3 H _{2} O$

$2\, mole$       $5 \,mol$

Moles of $O _{2}$ required $=5$ moles