Question

What is the oxidation number of chlorine in Al(ClO4)3?

Answer 1

Answer:

The oxidation number of chlorine in Al(ClO₄)₃ is +7  

Explanation:

As per the rule for assigning oxidation number, the oxidation number of Al and O is +3 and -2 respectively.

Lets us assume the oxidation number of Cl is x

+3 + [x + 4(-2)] x 3 = 0

+ 3 + 3x -24 = 0  

3x -21 = 0  

3x = 21

x = 7

Answer 2

It would be +7 oxidation number.
(All compounds are zero)
Al is in group lll ( or 13 depending on the system) so the oxidation state is 3.
You have 12 O at -2 each for -24. That leaves you at -24+3= -21. So 3 Cl atoms must be +21 to balance the -21 there which makes +21/3 or +7 for each Cl.