Consider the following reaction: SO2Cl2(g)⇌SO2(g)+Cl2(g) A reaction mixture is made containing an initial [SO2Cl2] of 2.1×10−2 M . At equilibrium, [Cl2]= 1.1×10−2 M .Calculate the value of the equilibrium constant (Kc).

0.012

Explanation:

Let's consider the following reaction.

SO₂Cl₂(g) ⇌ SO₂(g) + Cl₂(g)

We can find the concentrations at equilibrium using an ICE Chart.

         SO₂Cl₂(g) ⇌ SO₂(g) + Cl₂(g)

I          2.1 × 10⁻²        0            0

C              -x              +x          +x

E        2.1 × 10⁻²-x       x            x

We know that the concentration of Cl₂ at equilibrium is 1.1 × 10⁻² M, so x = 1.1 × 10⁻² M.

The concentrations at equilibrium are:

[SO₂Cl₂] = 2.1 × 10⁻²-x = 2.1 × 10⁻²- 1.1 × 10⁻² = 1.0 × 10⁻² M

[SO₂] = [Cl₂] = x = 1.1 × 10⁻² M

The concentration equilibrium constant (Kc) is:

Kc = [SO₂] × [Cl₂] / [SO₂Cl₂]

Kc = 1.1 × 10⁻² × 1.1 × 10⁻² / 1.0 × 10⁻²

Kc = 0.012