Question
Question: > A 40 ml of a mixture of H2 and O2 at 18<sup>0</sup>C and 1 atm pressure was sparked so that the fo...
A 40 ml of a mixture of H2 and O2 at 180C and 1 atm pressure was sparked so that the formation of water was complete. The remaining pure gas had a volume of 10 ml at 18ºC and 1 atm pressure. If the remaining gas was H2, the mole fraction of H2 in the 40 ml mixture is :
A
0.75
B
0.5
C
0.65
D
0.85
Answer
0.75
Explanation
Solution
(1)
H2 +1/2O2 → H2O(l)
a b 0
a–2b 0 b
Reaction is studied at constant P &T.
a+b = 40 a–2b = 10
a = 30 ml b = 10ml
mole fraction of H2 = volume fraction of H2 =30/40 = 0.75.