Buffer solutions

Question 1

buffer solution

Answer 1

a system that minimises pH changes when small amounts of acid and a base are added.

• consists of two components to remove an added acid/ alkali; a weak acid and a conjugate base.

Question 2

preparation of weak acid buffer solutions

1) Weak acid from salt

Answer 2

mis solution of ethanoic acid CH3COOH and CH3COONa Sodium ethanoate.

• Add ethanoic acid to water = partially discssociates and amount of ethanoate ions in solution is very small.
• CH3COOH ⇌ H+ + CH3COO-
• salts of weak acids are ionic compounds so prov

Question 3

why r salts of weak acids convenient sources of conjugate bases?

Answer 3

salts of weak acids are ionic compounds ; when added to water the salt completely dissolves , dissociation into ions is complete so a source of conj base component.

Question 4

2) Weak acid buffer solution from strong alkali .

Answer 4

adding aqueous solution of an lakali such as NaOH to an excess of the weak acid.
Weak acid is partially neutralised by alkali ; forms conj base (salt of weak acid) and since weak acid is in excess there is some of weak acid left over unreacted.

result ; mixture of salt of weak acid an dany unreacted weak acid.