3.1.7 - Oxidation, Reduction and Redox

Question 1

What is oxidation?

Answer 1

The process of electron loss.

Question 2

What is reduction?

Answer 2

The process of electron gain.

Question 3

What is a disproportion reaction?

Answer 3

An element is both oxidised and reduced.

Question 4

Define oxidation and reduction in terms of electron transfer.

Answer 4

Oxidation is the loss of electrons, resulting in an increase in oxidation number. Reduction is the gain of electrons, resulting in a decrease in oxidation number.

Question 5

What is the role of oxidising and reducing agents in a redox reaction?

Answer 5

An oxidising agent gains electrons and is reduced in the reaction, while a reducing agent loses electrons and is oxidised.

Question 6

How to assign oxidation numbers to elements in compounds and ions?

Answer 6

The sum of oxidation numbers in a molecule equals zero; in a polyatomic ion, it equals the ion’s charge. Oxidation numbers for group elements are usually fixed (e.g., Group 1 metals are +1), while for transition metals and others it may vary and requires calculation based on molecule or ion composition.

Question 7

Describe how to write a reduction half-equation for the conversion of MnO4- to Mn2.

Answer 7

Start with MnO4- adding electrons to reflect the change in oxidation state from +7 to +2, balance oxygen atoms with H2O on the product side, and then add H+ on the reactant side to balance the hydrogen atoms from H2O. Ensure the charge is balanced.