Chemistry · Oct / Nov 2023 · Paper 11 · Question 18

Aqueous bromine is an equilibrium mixture. Br2(aq) + H2O(l) ⇌ OBr−(aq) + Br−(aq) + 2H+(aq) Aqueous bromine is orange in colour. The species on the right-hand side of the equation are colourless. Changes are made to three separate portions of the equilibrium mixture. Which row shows how the colour of the mixture changes when a small amount of each substance is added?

1. Aadding sulfuric acid: darker orange; adding solid sodium bromide: darker orange; adding water: darker orange
2. Badding sulfuric acid: darker orange; adding solid sodium bromide: darker orange; adding water: paler orange
3. Cadding sulfuric acid: darker orange; adding solid sodium bromide: paler orange; adding water: darker orange
4. Dadding sulfuric acid: paler orange; adding solid sodium bromide: darker orange; adding water: paler orange

As printed in the paper