Question

An organic compound, whose vapour density is 45, has the following percentage composition,

H = 2.22%, O = 71.19% and remaining carbon. Calculate its molecular formula.

Answer 1

The molecular weight of the compound = 90

Empirical formula weight of the compound = 12 + 1 + 2 x 16 = 45

n = `"Molecular weight"/"Empirical formula weight"`

= `90/45`

= 2

∴ Molecular formula of the compound = (CHO₂)₂

= C₂H₂O₄

= (COOH)₂