Question

A compound contains 69.5% oxygen and 30.5% nitrogen and its molecular weight is 92. The formula of that compound is 

(a) N₂O

(b) NO₂

(c) N₂O₄

(d) N₂O₅

Answer 1

Correct option is (c) N₂O₄

Mole atoms of oxygen = \(\frac{69.5}{16}\) = 4.34

Mole atoms of nitrogen = \(\frac{30.5}{14} \) = 2.18

Ratio of mole atoms of N and O = 2.18 : 4.34 = 1 : 2

 Empirical formula = NO₂,

Molecular formula = (NO₂)n 

Where n = \(\frac{\text{Molecular mass}}{\text{Empirical formula mass}}\)

\(= \frac{92}{46}\)

= 2