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Pertanyaan

Di dalam 200 ml larutan terlarut 5,35 gram NH4CL jika Kb=10^-5 , Ar N=14 , H =1 ,CL = 35,5 hitunglag pH larutan tersebut

1 Jawaban

  • Mr = 14 + 4 + 35,5
    Mr = 53,5

    mol = gr / Mr
    mol = 5,35 / 53,5
    mol = 0,1 mol

    M = mol / liter
    M = 0,1 / 0,2
    M = 0,5

    Kb = tetapan ionisasi basa = 10^-5

    [OH-] = √kb [NH4CL]
    [OH-] = √10^-5 (0,5)
    [OH-] = √5 x 10^-6
    [OH-] = √5 x 10^-3

    pOH = - log [OH-]
    pOH = 3 - log√5

    pH = 14 - (3 - log√5)
    pH = 14 - 3 + log√5
    pH = 11 + log√5

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