Higher Chemistry | Unit 1 | Oxidising and Reducing Agents

Oxidation reaction

- The loss of electrons by a reactant, or the gain of oxygen (increase in oxygen:hydrogen)

- Any metal reacting to form a compound (atom→ion)

Reduction reaction

- The gain of electrons by a reactant, or the loss of oxygen (decrease in oxygen:hydrogen).

- Any compound reacting to form a metal (ion→atom)

Redox reaction

When an oxidation and reduction reaction occur at the same time, where the metal higher on the electrochemical series is oxidised and the metal lower is reduced.

Why are H+ ions needed in some redox reactions?

H+ (aq) ions are used as a reactant.

Oxidising agent

- A substance that removes electrons from other chemicals, and gains electrons for itself.

- Causes other chemicals to oxidise by reducing itself.

- Strongest oxidising agents found in group 7, and bottom left of electrochemical series (MnO₄^- and Cr₂O₇^2- in acidic solutions (group ions), H₂O₂ (molecule)

Uses of oxidising agents

- Can kill bacteria and fungi, and inactivate viruses.

- Can break down coloured compounds and be used as bleach for clothes or hair.

Reducing agent

- A substance that donates electrons to other chemicals, and loses electrons for itself.

- Causes other chemicals to reduce by oxidising itself.

- Strongest reducing agents found in group 1, and top right of electrochemical series, eg. carbon monoxide gas

Self-indicating titration

A titration which has a visible endpoint with a colour change involving one of the reactants.