The formula of a compound that is formed by the Aluminium and Sulphur is:

The oxidation state and covalency of Al in [AlCl(H₂O)₅]²⁺ are respectively:

1. +3 and 3
2. +6 and 2 
3. +3 and 6
4. +2 and 2 

Consider the following reaction.
Na₂O + H₂O → A
Cl₂O₇ + H₂O → B
The product A and B are respectively:
1. A is NaOH; and B is HOCl
2. A is NaH; and B is HOCl
3. A is NaH; and B is HClO₂ 
4. A is NaOH; and B is HClO₄