15 moles of H2 and 5.2 moles of I2 are mixed and allowed to attain equilibrium at 500ºC. At equilibrium, the HI is found to be 10 moles. The equilibrium constant for the formation of HI is.

2 2 H I 2HI Let both 2 H and 2I are 1 mole each, and HI will be 2 mole if 10 mole HI will produce, then 2 H and 2I must be 5 moles each. at equilibrium conc. left for 2 H 15 5 10 mole, 2I 5.2 5 0.2 mole and HI 10 mole 2 2 C 2 2 HI 10 100 K = = = = 50 H I 10×0.2 2