Year 12- Redox (Physical Chemistry)

Question 1

What is oxidation?

Answer 1

• Loss of electrons

- Increase in oxidation number

Question 2

What is reduction?

Answer 2

• Gain of electrons

- Decrease in oxidation number

Question 3

Rules of oxidation numbers

Answer 3

1) All uncombined elements have an ON of 0
2) ON of elements in compounds add up to 0
3) ON of monoatomic ions is equal to the ionic charge
4) In a polyatomic ion, the sum of the individual ONs of the elements adds up to the ions charge
5) Group 1= +1, Group 2= +2
6) Al= +3, F= -1
7) H=+1 , except when in metal hydrides -1
8) Cl, Br, I= -1, except with O and F
9) O= -2 except in peroxides where its -1 and with F

Question 4

What is an oxidising agent?

Answer 4

An electron acceptor. It is itself reduced.

Question 5

What is a reducing agent?

Answer 5

An electron donor. It is itself oxidised.