Question

A gas mixture contains acetylene and carbondioxide 40L of this mixture requires 40L of oxygen under the same conditions
for complete combustion. The percentage of acetylene in the mixture is
(A) 50%
(B) 40%
(C) 60%
(D) 75%

Answer 1

Given:

Mixture contains Acetylene and Carbon dioxide.

Volume of mixture = 40 L

Volume of oxygen required for complete combustion = 40 L

To Find:

% composition of Acetylene in the mixture.

Calculation:

- CO2 does not undergo combustion. So only acetylene will be combusted.

- It is given as:

C2H2 + 5/2 O2 → 2 CO2 + H2O

⇒ Volume of acetylene that requires 56 L (2.5 mole) oxygen = 22.4 L (1 mole)

⇒ Volume of acetylene that requires 40 L oxygen = (22.4 / 56) × 40

⇒ V = 16 L

- % composition of acetylene = (16 / 40) × 100 = 40 %

- Hence, the correct answer is option (B) 40%.