Sodium formate HCOONa is a weak base and undergoes hydrolysi

Sodium formate, HCOONa, is a weak base and undergoes hydrolysis in water. Determine the OH- concentration at equilibrium in a solution that has an initial sodium formate concentration of 0.0658M. Kb for the formate ion is 5.88 x 10^-11

Solution

HCOONa

so Ka=1.7*10^-4

since it is a salt of weak acid and stong base,

pH=7+0.5pKa+0.5logC

=7+0.5*3.77+0.5*log(0.0658)

=8.294

so,

pOH=14-8.294

=5.706

so [OH-]=10^-5.706

=1.97*10^-6 M