43 M What is the ph ofthis CM Spluatibwhatwtttuunadhalesny L

43 M What is the ph ofthis CM Spluatib.whatwt.ttuunadhalesny. Lylalyi us.LEary) the the\'sLE Armed willvade to 2

Solution

Kb of formate is given = 9.9 x 10^-11

Kb x Ka = Kw

9.9 x 10^-11 x Ka = 1.0 x 10^-14

Ka = 1.0 x 10^-4

pKa = -log Ka

pKa = -log (1.0 x 10^-4)

pKa = 4.00

pH = pKa + log [HCOOK / HCOOH]

pH = 4.00 + log (0.43 / 0.5)

pH = 3.93

common ion which is present in same of two solutions . here common ion HCOO-

salt of formic acid will involve in the hydrolysis reaction. formate ion will participate in the hydrolysis reaction

HCOO- (aq) + H2O (l) ------------------------------> HCOOH (aq) + OH- (aq)