Sebanyak 600 ml larutan Ba(OH)2 memiliki ph = 12 direaksikan dengan 100ml HClbyg memiliki ph = 2. Besar ph campuran Ba(OH)2 dan HCl adalah

pH Ba(OH)2 = 12
pOH = 14 - 12 = 2
[OH-] = 10^-2

[OH-] = b x Mb
10^-2 = 2 x Mb
Mb = 10^-2/2 = 5 x 10^-3 M

pH HCl = 2
[H+] = 10^-2

[H+] = a x Ma
10^-2 = 1 x Ma
Ma = 10^-2

mol Ba(OH)2 = M x V = 5 x 10^-3 x 600 = 3 mmol

mol HCl = M x V = 10^-2 x 100 = 1 mmol

2HCl + Ba(OH)2 -> BaCl2 + 2H2O
m 1 3 - -
r 1 0,5 0,5 1
s - 2,5 0,5 1

Mcampuran = mol/Vtotal = 2,5/700 = 0,0035 M

[OH-] = b x Mb = 2 x 0,0035 = 0,007

pOH = - log [OH-] = - log (7 x 10^-3) = 3 - log 7

pH = 14 - (3 - log 7) = 11 + log 7