Question

Calculate the pH of each aqueous solution: I need step to step solution please using formula from;

pH = -log [H3O+]

pOH = -log[OH-]

pH + pOH = 14

1)0.80 M lactic acid and 0.40 M lactate ion. 2) 0.10 mol of formic acid, HCOOH, and 0.10 mol of sodium formate, HCOONa in 1 L of water . 3) 0.30 M NH₃ and 1.50 M NH₄⁺

Answer 1

1. PH   = PKa + log[lactate ion]/[lactic acid]

           = 3.86 + log0.4/0.8

            = 3.86-0.3010

            = 3.559

2. PH = Pka + log[HCOONa]/[HCOOH]

            = 3.75 + log0.1/0.1

              = 3.75

3. POH = PKb + log[NH4^+]/[NH3]

                = 4.75 + log1.5/0.3

                 = 4.75+ 0.6989

                 = 5.4489

PH = POH = 14

PH          = 14-POH

                  = 14-5.4489   = 8.5511