What is the pKb of Formate ion?

0.64M ........... 8.77 pH

Help!! I'm not sure how to calculate this... I know to use the Kb formula but I'm not sure where to plug the numbers in.

2 answers

....................formate + HOH ==> Hformate + OH^-
I...................0.64.............................0................0
C...................-x................................x................x
E.................0.64-x............................x...............x

Kb for formate = (Kw/Ka for formic acid) = (x)(x)(0.64-x)
Notes: Hformate is formic acid HCOOH.
Convert pH to pOH and convert that to (OH^-). Plug that in for x. Solve the equation for Ka, convert to Kb from KaKb = Kw = 1E-14

Post your work if you get stuck.
bro bob...