Oxidising & Reducing Agents

Question 1

An oxidising agent is

Answer 1

An oxidising agent is a substance that oxidises another atom or ion by causing it to lose electrons

Question 2

What happens to a oxidising agent in a reaction

talk about what happens to the oxidation state

Answer 2

An oxidising agent itself gets reduced – it gains electrons

Therefore, the oxidation state of the oxidising agent decreases

Question 3

A reducing agent is a

Answer 3

A reducing agent is a substance that reduces another atom or ion by causing it to gain electrons

Question 4

What happens to a reducing agent in a reaction

talk about what happens to the oxidation state

Answer 4

A reducing agent itself gets oxidised – it loses/donates electrons

Therefore, the oxidation state of the reducing agent increases

Question 5

For a reaction to be a redox reaction, there must be

Answer 5

both an oxidising and reducing agent present

Question 6

Some substances can act both as oxidising and reducing agents - look at the two roles of H2O2 in the previous examples
The role they take is dependent on what they are reacting with and the reaction conditions

Question 7

Iron can be both +2 and +3 so Roman numerals are used to distinguish between them
Fe2+ in FeO is written as iron(II) oxide
Fe3+ in Fe2O3 is written as iron(III) oxide