JEE Advanced levelSingle correct optionDifficulty 3 of 3ce202
NX2OX4(g)2NOX2(g) is 20\% dissociated at a total pressure of 1.0atm and temperature T. At the same temperature the total pressure is raised to 3.0atm. The new degree of dissociation is
A0.200
B0.117
C0.067
D0.100
Answer: B
Kp=4α2P/(1−α2)=0.1667 atm. At 3 atm, α=Kp/(Kp+4P)=0.1667/12.1667=0.1170. The inverse-proportion guess (0.2/3) is wrong because α∝P−1/2 only approximately.