The ph of a 0.013m weak monoprotic acid solution is 5.27. calculate ka for this acid

Given:

pH is 5.27

Concentration of sol'n 0.013m (weak monoprotic)

Determine H + concentration:

[H+] = 10^-pH

= 10^-5.27

= 5.37x10^-6

Ka = [H+] [A-] / [HA]

= (5.37x10^-6) * (5.37x10^-6) / (0.013 - 5.37x10^-6)

= 2.22x10^-9