Chemistry · May / June 2026 · Paper 12 · Question 15

Elements X and Y react together in a reversible reaction to form XY2. X + 2Y ⇋ XY2 1.0 mol of X is mixed with 1.0 mol of Y and the mixture is left to react until an equilibrium position is reached. Which statements about this reaction are correct? 1 After the equilibrium position has been reached, the reaction stops. 2 At equilibrium, there is more than 0.5 mol of X present. 3 At equilibrium, there is less than 1.0 mol of XY2 present.

1. A1, 2 and 3
2. B2 and 3 only
3. C2 only
4. D3 only

As printed in the paper