Question

Butyric acid contains C,H,O. When 2.24g sample of butyric acid is completely burned, it gives 8.45g of co2 and 3.46g of h2o. What is the mass% of each element in butyric acid and what is the molecular and of butyric acid?(molar mass of butyric acid=88 )

Answer 1

Answer:

In CO2 the no of C atom is 1.

it means 44 mg of CO2 = 12 mg C

and 8.45 mg = 12 X 8.45 / 44

=2.30mg

% of C = 2.30 X 100 / 4.24

= 54.3 %

Similarly in H2O = 2H

in 3.46mg of H2O H = 2 X 3.46 /18

= 0.384mg

% of H = 0.348 x100 / 4.24 =9 %

% of O = 100 - 63.3

= 36.7%

By calculation we get the simple whole no ratio = 2:4:1

so empirical formula is C2H4O

and the value of n= 88 /44 =2

so molecular formula = c4 H8 O2