Question

A compound with an empirical formula of CHO2 has a vapour density of 67.5. Find its molecular
formula. [ C = 12, H = 1 O = 16 ]

Answer 1

Empiricaz formula is CH

2

O

Mass of Empirical formula =12+12+16=30g

Vapour density =

2

Molar mass of compound

∴90=

2

Molar mass

Molar mass of compound =180g

On dividing the

Empirical formula mass

Molecular formula mass

n=

30

180

=6

On multiply each atom of empirical formula by n we get actual molecular formula

C×+H

2

×6+O×6=C

6

H

12

O

6

The molecular formula of compound is C

6

H

12

O

6

with molar mass 180.