pKa pKb and neutrality

[Gabrielle Arreglo 3F]

When pKa and pKb are equal does that mean that the solution is neutral? (and when pKa<pKb, it is acidic, and vice versa?)

[Gia Leon 2A]

In short; yes :)

it indicates that the solution is at its equilibrium point, and the concentrations of the acidic and basic forms of the species are equal.

If pKa<pKb: The solution is acidic. (conjugate acid)

If pKa>pKb: The solution is basic. (conjugate base)

[Tim D 3B]

The answer as far as I am aware is yes. However I think it is important to consider what pKa and pKb symbolize and why this would mean their are neutral. pKa is a value that explains to what degree an acid will dissociate in water and pKb is that for a base. So if you consider and acid and a base in an equation, both the acid and base have a different degree to which they dissociate. However if pKa and pKb are equal, they will both neutralize each other during the reaction, as the rates are exactly the same. For this same reason if pKa is less than pKb, then more of the base will dissociate leaving the equilibrium of the solution to be acidic.

[Emma Jacquay 2F]

Another important thing to know is that when pKa is small that means that the acid is strong, and the base is weak. Likewise, when pKa is big the acid is weak and the base is strong...the same goes for pKb when it is small the base is strong and acid weak and when pKb is large the base is weak and the acid is strong.

[Kaili 3H]

Yes, you are correct that when pKa and pKb are equal, it generally means the solution is neutral. This also indicates that the acid and its conjugate base are equally strong. Therefore, we can also conclude (as you mentioned) that if pKa < pKb, the solution is acidic because the acid is stronger than the base. Also, if pKa > pKb, the solution is basic and the base is stronger than the acid.