2.1.5: Redox

Question 1

Give an example of a reduction ionic equation for calcium

Ca + 1/2 O2 = CaO

Answer 1

1/2 O2 + 2e- = O2-

Question 2

Give an example of a oxidation ionic equation for calcium

Ca + 1/2 O2 = CaO

Answer 2

Ca = Ca2+ + 2e-

Question 3

Give the redox equations for the following reaction
2Fe + 3Cl2 = 2FeCl3

Answer 3

Fe is oxidised and is the reducing agent
2Fe = 2Fe3+ + 6e-

Cl is reduced and is the oxidising agent
3Cl2 + 6e- = 6Cl-

Question 4

Give equation for oxidation of magnesium as it loses 2 electrons

Answer 4

Mg → Mg2+ + 2e−

Question 5

Acid + metal hydroxide = ?

Answer 5

Salt + water

Question 6

What is formed when magnesium reacts with water ?

Answer 6

Magnesium hydroxide and hydrogen

Question 7

Define reducing agent

Answer 7

A species that reduces another species by adding one or more electrons and is oxidised itself so its oxidation number increases

Question 8

Define oxidising agent

Answer 8

A species that oxidises another species by removing one or more electrons and is reduced itself so its oxidation number decreases

Question 9

Define disproportionation reaction

Answer 9

A reaction where the SAME element is both oxidised and reduced

Question 10

Define reduction

Answer 10

Gain of electrons and decrease in oxidation number

Question 11

Define oxidation

Answer 11

Loss of electrons and increase in oxidation number

Question 12

What is the exception rule for hydrogen in redox ?

Answer 12

+1 except for -1 in hydrides when a metal is bonded to hydrogen

Question 13

What is the exception rule for chlorine in redox ?

Answer 13

-1 except when bonded with F and O and it is a positive value

Question 14

What is the exception rule for oxygen in redox ?

Answer 14

-2 except in peroxides where it is -1 and in OF2 where it is +2

Question 15

What do roman numerals represent ?

Answer 15

Oxidation states