Determining salts/pKa,pKb

[Alina Garmash-3I]

How do I determine whether the solution will be basic or acidic? How does the pKa/pKb relate to solutions and charged ions(referring to the last two problems on achieve)?

[ishankhurana2D]

Hello! In terms of pKa's relationship to pH and pOH:

For a base:
When pH < pKa of conjugate acid, there is more conjugate acid (BH+, charged) than there is base (B, neutral), so the solution is predominantly charged.
When pH > pKa of conjugate acid, there is more base (B, neutral) than conjugate acid (BH+, charged), so the solution is predominantly neutral.

For an acid:
When pH < pKb of a conjugate base (meaning pH > pKa of the original acid), there is more conjugate base (A-, charged) than there is acid (HA, neutral), so the solution is predominantly charged.
WHen pH > pKb of a conjugate base (meaning pH < pKa of the original acid), there is more acid (HA, neutral) than there is conjugate base (A-, charged) so the solution is predominantly neutral.

I hope this helps!