Question

An organic compound on analysis gave the following data - carbon = 57.82% hydrogen = 3.6% and rest Oxygen... If molar mass is 166 then calculate the empericaland and molecular formula.

Answer 1

Carbon = 57.82 %Hydrogen = 3.6 %Remaining = 100- (57.82+3.6) = 38.58 % oxygenSo, Empirical formula is : C H O .Molar mass of the compound = 166 gMass of empirical formula =12 ×4 +1 ×3 +16 ×2 = 83 gHence, Molecular formula =2 ×empirical formula = C8H6O4

Answer 2

Explanation:

Molecular formula = 2 x V.D. = 2 x 83 = 166

% of Hydrogen =100−(57.82+38.58)=3.6

Element % Ratio Simplest Ratio Empirical formula

Carbon 57.82/12=4.82 4.82/2.41=2 C

4

H

3

O

2

Hydrogen 3.6/1=3.6 3.6/2.41=1.49

Oxygen 38.58/16=2.41 2.41/2.41=1

The empirical formula weight =12×4+3×1+16×2=83

Formula ratio =166/83=2

The molecular formula of compound =C

8

H

6

O

4