1.0 mol of H2 and 1.0 mol of I2 are heated in a 2.0 L vessel. At equilibrium, 1.3 mol of HI is present: H2(g) + I2(g) 2HI(g). Calculate K_c and give the answer to the nearest integer.

JEE Main levelNumerical answerDifficulty 2 of 3ce017

1.0 mol of $H X_{2}$ and 1.0 mol of $I X_{2}$ are heated in a 2.0 L vessel. At equilibrium, 1.3 mol of $HI$ is present: $H X_{2} (g) + I X_{2} (g) 2 HI (g)$ . Calculate $K_{c}$ and give the answer to the nearest integer.

Numerical answer type, tolerance 0.5.

HI formed is 1.30 mol, so

H X_{2}

and

I X_{2}

reacted

= 0.65

mol each, leaving 0.35 mol of each.

K_{c} = (1.30/2)^{2} / ((0.35/2) (0.35/2)) = 13.796

, i.e. about 14.