sebanyak 100 ml HCN 0,1 m di campur dengan 100 ml NaOH 0,05 m .hitung pH campuran ka=10 ^-5

Dik : HCN
M = 0,1
V = 100
Ka = 10^-5
NaOH
M = 0,05
V = 100
Dit : pH ?

[H+] = Ka . mol asam/mol garam
= 10^-5 . 10/5
= 20^-5
pH = - log [H+]
= - log [ 20^-5]
= 5 - log 20

n HCN = 100 ml . 0,1 M = 10 mmol
n NaOH = 100 ml . 0,05 M = 5 mmol

[H⁺] = Ka . n HCN / n NaOH
[H⁺] = 10⁻⁵ . 10 mmol / 5 mmol
[H⁺] = 2 × 10⁻⁵

pH = - log [H⁺]
pH = - log 2 × 10⁻⁵
pH = 5 - log 20