Some Basic Concepts Of Chemistry Question 30
Question: A mixture of $ O _2 $ and gas “Y” mol. mass 80 in the mole ratio a : b has a mean molecular mass 40. What would be mean molecular mass, if the gases are mixed in the ratio b : a under, identical conditions? (Assume that gases are non-reacting):
Options:
A) 40
B) 48
C) 62
D) 72
Show Answer
Answer:
Correct Answer: D
Solution:
[d] Let mole fraction of $ O _2 $ is $ x $ $ 40=32\times x+80( 1-x ) $ or $ x=5/6 $ $ a:b=x:( 1-x )=\frac{5}{6}:\frac{1}{6} $ When ratio is changed $ M _{mixture}=32\times \frac{1}{60}+80\times \frac{5}{6}=72 $
