7,4 gram Ca(OH)2 dilarutkan dalam air hingga volume larutan 500ml. Hitunglah pH larutan jika Mr Ca(OH)2 = 74

s = gr/Mr × 1000/mL
s = 7,4/74 × 1000/500
s = 1/10 × 2/1
s = 0,2
OH = 2×10 pangkat -1
POH = 1-log 2
pH = 14- (1-log 2)
pH = 13 + log 2
valensi basa = 2
pH = 13 + log 4

Larutan
Kimia XI

Basa kuat Ca(OH)₂ bervalensi 2 sesuai jumlah OH

M = [massa/Mr] x [1000/V ml]

M = [7,4/74] x [1000/500]

M = 0,2 molar

[OH⁻] = M x valensi

[OH⁻] = 0,2 x 2

[OH⁻] = 4 x 10⁻¹

pOH = - log [OH⁻] 

pOH = 1 - log 4

pH = 14 - pOH

pH = 14 - (1 - log 4)

Jadi pH = 13 + log 4 atau 13 + 2.log 2