Question

Hitunglah Ph dari 7,4 gram Ca(OH)2 (Mr=74 yang dilarutkan dalam 2 liter air!

Answer 1

Mol Ca(OH)₂ = 7,4/74 = 0,1 mol

Molaritas Ca(OH)₂ = mol/Volume = 0,1/2 = 0,05 M

[OH⁻] = Molaritas x valensi
[OH⁻] = 0,05 x 2
[OH⁻] = 0,1

pOH = -log [OH⁻]
pOH = -log [0,1]
pOH = 1

pH = 14 - pOH
pH = 13

Answer 2

Dilarutkan ke 2 liter air -------> 2000 ml


Ca(OH)₂ valensi = 2

[OH⁻] = M × valensi
[OH⁻] = 0,05 × 2
[OH⁻] = 0,1

pOH = -log [OH⁻]
pOH = -loh [0,1]
pOH = 1

pH = 14 - pOH
pH = 14 - 1
pH = 13