Oxidising and Reducing Agents

Question 1

What is reduction?

Answer 1

Reduction is a gain of electrons by a reactant in any reaction.

Question 2

What is oxidation?

Answer 2

Oxidation is a loss of electrons by a reactant in a reaction.

Question 3

What is an oxidising agent?

Answer 3

• An oxidising agent is a substance that accepts electrons.
• It will cause the other reactant to reduce.
• It is the substance in the reaction which is oxidising.

Question 4

What is a reducing agent?

Answer 4

• A reducing agent is a substance that donates electrons.
• It will cause the other reactant to oxidise.
• It is the substance in the reaction which is reducing.

Question 5

What is the role of electronegativity in redox?

Answer 5

• Elements with low electronegativities tend to form ions by losing electrons and so act as reducing agents.
• Elements with high electronegativities tend to form ions by gaining electrons and so act as oxidising agents.

Question 6

What groups have the strongest reducing or oxidising elements?

Answer 6

• The strongest reducing elements are metals in group 1 (alkali metals).
• The strongest oxidising elements are non-metals in group 7 (halogens).

Question 7

Name examples of oxidising or reducing compounds/molecules/ions.

Answer 7

• Hydrogen peroxide (H2O2) is a molecule that is an oxidising agent
• Dichromate (Cr2O7) and permanganate (MnO4) ions are group ions that are strong
  oxidising agents in acidic solutions.
• Carbon monoxide is a gas that can be used as a reducing agent

Question 8

What is the role of the electrochemical series in redox?

Answer 8

• The electrochemical series represents a series of reduction reactions
• The strongest oxidising agents are at the bottom of the left-hand column of the
• electrochemical series.
• The strongest reducing agents are at the top left-hand column of the electrochemical series.