kedalam larutan basa lemah LOH ditambah garam L2SO4 shingga konsentrasi LOH jadi 0,1M dan L2SO4 jadi 0,05M Kb LOH 10^-5 ph..?

Diketahui :
Molaritas LOH = 0,1 M
Molaritas L2SO4 = 0,05 M
Kb = 10^-5

Ditanya : pH campuran ?

Jawab :

Misal volume larutan adalah V.

n Basa (LOH) :
= M.V
= 0,1 MV

n Garam (L2SO4) :
= M.V
= 0,05 MV

[OH-] :
= Kb × n basa / n garam
= 10^-5 × 0,1 MV / 0,05 MV
= 2 × 10^-5

pOH :
= – log [OH-]
= – log 2 × 10^-5
= – ( log 2 + log 10^-5)
= – log 2 – log 10^-5
= 5 – log 2

pH campuran :
= 14 – pOH
= 14 – ( 5 – log 2)
= 14 – 5 + log 2
= 9 + log 2