Oxidising and Reducing Agents

Question 1

State the definitions of reduction and oxidation

Answer 1

Reduction is gain of electrons by a reactant (or loss of oxygen).

Oxidation is loss of electrons by a reactant (or gain of oxygen).

Question 2

State the definition of a redox reaction

Answer 2

A Redox Reaction is when an oxidation and a reduction reaction takes place at the same time.

Question 3

State the definition of an oxidising and reducing agent

Answer 3

Oxidising agent is a substance that accepts electrons (helps another reactant to be oxidised by being reduced itself).

Reducing agent is a substance that donates electrons (helps another reactant to be reduced by being oxidised itself).

Question 4

Recognise oxidising and reducing agents in reactions, on the Periodic Table and by using electronegativities

Answer 4

Elements with low electronegativities can form ions by losing electrons so act as reducing agents (elements with high electronegativities can act as oxidising agents).

Strongest reducing agents are in Group 1 of the Periodic Table (strongest oxidising agents are in Group 7).

Question 5

Identify compounds, ions and molecules that can act as oxidising or reducing agents

Answer 5

Oxidising agents are at the bottom of the left-hand side column of the electrochemical series:

permanganate (MnO4-)
dichromate (Cr2O72-)
hydrogen peroxide (H2O2)
Reducing agents are at the top right-hand column of the electrochemical series:
CO is a reducing agent

Question 6

State the uses of oxidising agents

Answer 6

Oxidising agents can be used to kill fungi and bacteria and also as a bleach.