Kimia

Pertanyaan

Ini soalnya ttg perhitungan ph hidrolisis garam
1. Dik larutan NaCl 0.02 m
Jika Ka 2.10pangkat-10 tentukan ph nya
2. Dik NH4Cl 0.01m jika Kb NH3 2.10pangkat-5 tentukn ph nya
3. Dik larutan CH3COOH4 0.1 m
Ka NH4OH 4.10pangkat-10
Kb CH3COOH 2.10pangkat-5 tentukan ph nya

1 Jawaban

  • 1.
    [OH-] = √Kw / Ka . M
    [OH-] = √10^-14 / 2 x 10^-10 (2 x 10^-2)
    [OH-] = √10^-4 x 10^-2
    [OH-] = √10^-6,
    [OH-] = 10^-3

    pOH = -log[OH-]
    pOH = -log 10^-3
    pOH = 3

    pH = 14 - 3
    pH = 11

    2.
    [H+] = √Kw / Kb . M
    [H+] = √10^-14 / 2 . 10^-5 . 1 x 10^-2
    [H+] = √10^-9 / 2 (10^-2)
    [H+] = √10^-11 x 0,5
    [H+] = √10^-12 x 5
    [H+] = √5 x 10^-6

    pH = -log[H+]
    pH = -log√5 x 10^-6
    pH = 6 - log√5

    3.
    [H+] = √Kw . Ka / Kb
    [H+] = √10^-14 . 4 x 10^-10 / 2 x 10^-5
    [H+] = √10^-19 x 2
    [H+] = √10^-18 x 0,2
    [H+] = √0,2 x 10^-9

    pH = -log [H+]
    pH = -log√0,2 x 10^-9
    pH = 9 - log√0,2

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