Question

A compound contains 80% carbon and 20% hydrogen . If vapour density of compound is 15 , the molecular formula of compound is​

Answer 1

Amount of C = 80%

Amount of H = 20%

1. Calculate Emperical Formula

80/ 12 : 20/1

6.67 : 20

20/3 : 20

20 : 60

2 : 6

1 : 3

Emperical formula : CH3

Emperical mass = 12 + 3 = 15

Molecular mass = 2 * VD = 2 * 15 = 30

Molecular mass = n * emperical mass

30 = n * 15

n = 2

Molecular formula = n * emperical formula

= 2(CH3)

= C2H6