Topic 2 - Redox in action

TESTS FOR OXIDISING AGENTS

• Some oxidising agents donate oxygen in their reactions, and these compounds will sometimes give off oxygen on heating. A substance such as ammonium nitrate fits in this group.

• If an oxidising agent is heated with hydrochloric acid it may oxidise the chloride ions to chlorine. Chlorine can be detected as it bleaches damp litmus paper.

• If an oxidising agent is added to potassium iodide solution (acidified with sulphuric acid) it may cause the oxidation of iodide ions to iodine. This causes the solution to go brown, and the presence of iodine can be confirmed by adding starch solution, which forms a blue colour with iodine.

TESTS FOR REDUCING AGENTS

• If potassium manganate(VII) (dark purple), acidified with sulphuric acid, is added to a reducing agent, the solution becomes colourless.

• Add a solution of bromine or iodine. A reducing agent will cause the reduction of these to ions. The bromine and iodine are…