Question

Calculate the pH of a solution that contains the following analytical concentrations:

a. 0.222 M H₃PO₄ and 0.411 M NaH₂PO₄

pH=

b. 0.0270 M in Na₂SO₃ and 0.0311 M in NaHSO₃

pH=

c. 0.270 M in HOC₂H₄NH₂ and 0.180 M in HOC₂H₄NH₃Cl

pH=

d. 0.0130 M in H₂C₂O₄ and 0.0400 M in Na₂C₂O₄

pH=

e. 0.0270 M in Na₂C₂O₄ and 0.0180 M in NaHC₂O₄

pH=

Answer 1

a. pH = pka1 + log(NaH2PO4/H3PO4)

    pka1 of H3PO4 = 2.12

pH = 2.12+log(0.411/0.222)

     = 2.39

b . pH = pka1 + log(NaHSO3/H2SO3)

      PKA1 OF h2so3 = 1.81

    pH = 1.81+log(0.027/0.0311)

        = 1.75

c. pH = 14 - (pkb+log(HOC2H4NH3Cl/HOC2H4NH2))

   pkb of HOC2H4NH2 = 4.502

   pH = 14-(4.502+log(0.18/0.27))

       = 9.67

d. pH = pka2 + log(Na2C2O4/H2C2O4)

   pka2 of oxalicacid = 4.27

    pH = 4.27+log(0.04/0.013)

       = 4.76

e. pH = pka2 + log(Na2C2O4/NaHC2O4)

   pka2 of oxalicacid = 4.27

    pH = 4.27+log(0.027/0.018)

       = 4.45