Penjelasan:

Diketahui

V H2SO4 (asam) = 300 ml

pH H2SO4 = 2

V Ba(OH)2 (basa) = 200 ml

pH Ba(OH)2 = 12 --> pOH = 14 - ph

= 14 - 12

= 2

Ditanya = pH campuran?

Langkah 1

cari konsentrasi H2SO4 dan Ba(OH)2

a. larutan H2SO4

H2SO4 --> 2 H^+ + SO4^2-

pH = 2

pH = - log [H+]

= - log 10^-2

[H+] = [asam] × valensi asam

10^-2 = [asam] × 2

[asam] = 10^-2 ÷ 2

= 5 × 10^-3

b. larutan Ba(OH)2

Ba(OH)2 --> Ba^2+ + 2 OH^-

pOH = 2

pOH = - log [OH-]

= - log 10^-2

[OH-] = [basa] × valensi basa

10^-2 = [basa] × 2

[basa] = 10^-2 ÷ 2

= 5 × 10^-3

langkah 2

cari pH Campuran

nb : mol = volume × konsentrasi

perbandingan koefisien = mol

reaksi : H2SO4 + Ba(OH)2 --> BaSO4 + 2 H2O

mula 1,5 mmol 1 mmol

reaksi 1 mmol 1 mmol 1 mmol 2 mmol

sisa 0,5 mmol - 1 mmol 2 mmol

bersisa asam kuat

[H+] = [asam] × valensi asam

= 0,5 / 300 × 2

= 3,33 × 10^-3

pH = - log [H+]

= - log 3,33 × 10^-3

= 3 - log 3,33