For this two complexes:
[Al(OH2)6]^3+ & [Fe(OH2)6]^3+
The Al^3+ one is moe acidic. Why?
I have found 2 answers:
1. The charge to size ratio of Al^3+ is higher so the charge-charge repulsion of this metal center and the acidic proton is also higher.
2. The Al^3+ has a higher polarizing power that it polarizes the O-H bond.
Which one is more suitable for explaining this case?
Is there any better explanation?