Question

Find the empirical formula and the molecular formula of an organic compound from the data given below:

 C = 75.92%, H = 6.32% and N = 17.76% The vapour density of the compound is 39.5. 

[C= 12, H= 1,N= 14]

Answer 1

Empirical Formula ⇒ C₅H₅ N

Vapour density = 39.5

Molecular Mass = 2 × V.D.

= 2 × 39.5 = 79

Empirical formula Mass = 12 × 5 + 5 × 1 + 1 × 14

= 60 + 5 + 14

= 79

n = \(\frac{Molecular\,formula\,mass}{Empirical\,formula \,mass}\)= \(\frac{79}{79}\)

Thus, both Empirical formula and Molecular formula are C₃H₅N.