4.5 moles each of hydrogen and iodine heated in a sealed 10 litre vessel. At equilibrium, 3 moles of HI was found. The equilibrium constant for H2(g)  +  I2(g)  ⇌   2HI(g) is

H2  +  I2  ⇌   2HIInitial conc. 4.5      4.5          0                     x         x           2xFrom question 2x = 3x=32=1.5So conc. at equilibrium 4.5 - 1.5 of  H2= 4.5 - 1.5 of I2 and 3 of HIK=HI2I2  H2= 3 × 33 ×3=1