Question

A liquid mixture of O2, CH4 and CO has the composition 32% O2, 16% CH4 and 52% CO, then what is the mole fraction of CH4?

(a) 0.1

(b) 0.2

(c) 0.25

(d) 0.5

This question was posed to me in an online interview.

My question comes from Analyses of Multicomponent Solutions and Mixtures in section Moles, Density & Concentration of Basic Chemical Engineering

Answer 1

Right answer is (b) 0.2

Explanation: Let the total weight of the mixture be 100 g, => weight of each component are 32 g, 16 g and 52 g respectively, => moles of O2 = 32/16 = 2, moles of CH4 = 16/16 = 1, moles of CO = 52/26 = 2 g, => mole fraction of CH4 = 1/5 = 0.2.