150 ml larutan CH3COOH 0,1 + 1000 ml larutan NaOH 0,1 m jika Ka CH3COOH = 10`5 hitung pH

Diketahui : [CH3COOH]= 0,1 M
V = 150 mL
[NaOH] = 0,1 M
V = 1000 mL
Ka CH3COOH = 10`5
Ditanya: pH....?
Jawab : nCH3COOH= V×M
= 150×0,1 = 15 mmol
nNaOH = V×M
= 1000×0,1= 100 mmol
buat reaksi.

CH3COOH+NaOH-> CH3COONa+H2O
A: 14 mmol 100 mmol - -
B: 100mmol 100mmol 100 mmol 100 mmol
_________________________________ _
S: -86mmol - 100 mmol 100 mmol

[H+]= Ka× na/ng
= 10`5 × -86/100
= 10`5 × -0,86
= -86×10`5
pH= 5-log 86
pH= 3,0