Question

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be

(a) CHO

(b) CH₄O

(c) CH₃O

(d) CH₂O

Answer 1

Ans. (d) CH₂O

Sol.

The mass % of - C = 38.71

                             H = 9.67

                             O = 100-(38.71+9.67) = 51.62

 

to find empirical formula - 

Elements	% in compound	atomic no	no of moles	simple ratio	simple ratio
C	38.71	12	38.71/12 = 3.22	3.22/3.22 = 1	1
H	9.67	1	9.67/1 = 9.67	9.67/3.22 = 3	3
0	51.62	16	51.62/16 = 3.22	3.22/3.22 = 1	1

empirical formula = CH₂O