Question

Prediction?

1. How will the addition of an inert salt affect the PH and buffer capacity of a buffer?

2. What will happen to the ph and buffer capacity of a buffer when it is heated? what factors contribute to the answer?

3. What will happen to the ph of the solution when a buffer breaks down upon addition of acid?

4. What will happen to the ph of the solution when a buffer breaks down upon addition of base?

Answer 1

1) AS the addition of an inert salt is done it will not affect the PH and buffer capacity of a buffer because it neither react withacid buffer ( weak acid [A-] or its salt [HA] ).

2)Temperature can affect pH. Since pH of a buffer depends on the pKa of the weak acid, and pKa is the negative log of the Ka, and the Ka (dissociation constant) depends on temperature, so will the pH of a buffer.

and it depend whether the buffer is acidic or basic .

3) when a buffer breaks down upon addition of acid it means that the acid which is added is in excess .

as pH= pKA + [A^]-/ [HA] so on addition of acid [A]^- combines with it to form [HA] and the concerntration of [A]^- decrases   as all [A]^- combines with the acid (proton H+) then the any addition of acid will increase H+ concerntration and pH of solution decreases this is called buffer breaks down .

4)

when a buffer breaks down upon addition of base it means that the acid which is added is in excess .

as pOH= pKB + [B]+ / [BOH] so on addition of base [B]+combines with it to form   [BOH] and the concerntration of [B]+ increses  .A s all [B]+ combines then the any addition of base will increase OH^-concerntration and pOH of solution decreases this is called buffer breaks down .

as pH of solution decreases PH of solution increases

AS pH+pOH= 14 .