Redox

Question 1

7 elements with invariable oxidation numbers in their compounds

Answer 1

Grp 1 = +1
Grp 2 = +2
Al = +3
H = +1 (except metal hydrides where it’s -1 eg NaH)
F = -1
Cl,Br, I = -1 (except in compounds with oxygen/fluorine)
O = -2 (except peroxides like H2O2 where it is -1 and in compounds with fluorine)

Question 2

Oxidising agents are

Answer 2

reduced

Question 3

Reducing agents are

Answer 3

oxidised

Question 4

How to balance half eqns in acidic conditions?

Answer 4

1. Balance Os by adding water
2. Balance Hs by adding H+
3. Balance overall charge with electrons