Question

500 ml of 0.2 m acetic acid are added to 500 ml of 0.30 m sodium acetate solution if the dissociation constant of acetic acid is 1.5Ã10^-5 then ph of the resulting solution is

Answer 1

Acetic acid = ACOH

Sodium acetate = NaOAC

According to Henderson's Equaton,

   pH = pKa + log [salt]/[acid]

=> pH    = -log[1.5*10^(-5)] + log [0.3/0.2]

=> pH    =5

pH of the resulting solution is 5.

Buffer solution> A buffer solution  is an aqueous solution consisting of a mixture of a weak acid and its salt or vice versa. Its pH remains unchanged when a small amount of strong acid or base is added to it. Example, the bicarbonate buffering system is used to regulate the pH of blood.