Question

At 25 °C, Kc = 0.145 for the following reaction in the solvent CCl4. 2BrCl Br2 + Cl2 If the initial concentrations of each substance in a solution are 0.0549 M, what will their equilibrium concentrations be? [BrCl] = M the tolerance is +/-2% [Br2] = M the tolerance is +/-2% [Cl2]

Answer 1

                    2BrCl       ------>      Br2     +     Cl2

initially       0.0549                  0.0549       0.0549

at equili   (0.0549 - 2x)       (0.0549 + x) (0.0549 - x)

Kc = [Br2] [Cl2] / [BrCl]^2

0.145 = (0.0549+x) (0.0549+x) / (0.0549 - 2x)^2

x = 0.0193

[BrCl] = (0.0549 - 2*0.0193) = 0.0163

[Br2] = (0.0549 + 0.0193) = 0.0742 = [Cl2]