JEE Advanced levelSingle correct optionDifficulty 3 of 3ce095
Pure A(g) at 2.0 atm is introduced into a rigid vessel at constant temperature and dissociates by A(g)B(g)+C(g). At equilibrium the total pressure is 2.5 atm. Kp (in atm) is
A0.208
B0.167
C0.125
D0.133
Answer: B
Let x be the pressure of A that reacts: total pressure =2.0+x=2.5, so x=0.5 atm. Then pA=1.5, pB=pC=0.5 atm and Kp=(0.5)(0.5)/1.5=0.167 atm.