Question

Jika 200ml larutan HCl 0,2 dicampur dengan 400ml larutan HCl 0,05M . Maka harga PH larutan yang didapat sebesar?

Answer 1

Diketahui :
Larutan HCl Pertama
V HCl 1 = 200 mL
[HCl] 1 = 0,2 M

Larutan HCl Kedua
V HCl 2 = 400 mL
[HCl] 2 = 0,05 M


ditanya :
pH larutan campuran =. .. ?

V total = V HCl 1 + V HCl 2 = 200 mL + 400 mL = 600 mL

n HCl 1 = [HCl] 1 × V HCl 1 = 0,2 M × 200 mL = 40 mmol
n HCl 2 = [HCl] 2 × V HCl 2 = 0,05 M × 400 mL = 20 mmol

n total = n HCl 1 + n HCl 2 = 40 mmol + 20 mmol = 60 mmol

[HCl] total = n total / V total = 60 mmol / 600 mL = 0,1 M

[HCl] = [H+] = 0,1 M

pH = - log [H+] = - log (0,1) = 1