Question

a) Calculate the concentration of OH− in 1.54 M CH3CO2H?

b) Calculate the pH of 0.0229 M CH3CO2H?

c) Calculate the concentration of H3O+ in 0.0229 M CH3CO2H?

d) Calculate the concentration of CH3CO−2 in 0.0229 M CH3CO2H?

e) Calculate the concentration of CH3CO2H in 0.0229 M CH3CO2H?

Answer 1

a) pH of weak acid = 1/2(pka-logc)

                   = 1/2(4.756-log1.54)

                 = 2.284
[H+] = 10^(-PH)

     = 10^(-2.284) = 0.0052 M

b) pH = 1/2(4.756-log0.0229)

     = 3.198

c) [H+] = 10^(-PH)

     = 10^(-3.198) = 0.000634 M

d) [H+] = [CH3COO-] = 0.000634 M

e) KA = [H+][CH3COO-]/[CH3COOH]

1.75*10^(-5) = (0.000634^2)/X

X = 0.0229 M = [ch3cooh]