A mixture of 0.3 mole of H2 and 0.3 mole of I2 is allowed to react in a 10 litre evacuated flask at 500ºC. The reaction is H I 2HI , the K is found to be 64. The amount of unreacted 2I at equilibrium is

2 2 H I 2HI >> K=64 , value of K is high, so reaction goes to completion Volume=10L, no. of moles of 2 2 n H = 0.3& I = 0.3 C = V 2 2 0.3 0.3 H = = 0.03M & I = = 0.03M 10 10 Initial conc. 2 2 0 0.03 0.03 H I 2HI equilibrium conc. 0.03 - x 0.03 – x 2x 2 2 C 2 2 2x 2x K = 64 = 0.03-x 0.03-x >> 2 64 8 0.03 x x >> 2 0.24 8 10 0.24 0.24 0.024 10 x x x x >> Conc. left 2I 0.03M 0.024M 0.006M n C V 0.006 10 >> x x 0.06 mole.