Question

How do you know that Al(OH)3(s) is a base?

Answer 1

It has an incredibly high pH, and anything above 7 on the pH scale is a base

Answer 2

Explanation:

Bases are those substance which releases hydroxide ions in aqueous solution when dissolved in water.

$BOH(aq)\rightarrow B^+(aq)+OH^-(aq)$

As we can see that in formula of aluminium hydroxide , there are 3 hydroxide ions attached to single aluminum ion. So, when we will dissolve the aluminum hydroxide in water it will give aluminum ions and hydroxide ions in its solution.

$Al(OH)_3(aq)\rightarrow Al^{3+}(aq)+3OH^-(aq)$