calculate the value of pKa for the acid HA

Question

[HA] = 0.120 M

[H+] = 3.00 x 10^-4 M

[A-] = 3.00 x 10^-4 M

Answer 1

Ka = [H⁺][A^-]/[HA]

Ka = [3x10^-4][3x10^-4]/0.120

Ka = 9x10-8/0.12

Ka = 7.5x10^-7

pKa = -log Ka = -log 7.5x10^-7

pKa = 6.12