Soal 01
Perhatikan tabel persamaan reaksi hidrolisis berikut ini!
Nomor | Rumus Garam | Reaksi Hidrolisis | Uji lakmus merah | Uji lakmus biru | Sifat |
(1) | \(\ce{Na2SO3}\) | \(\ce{SO3}_{(aq)} ^{2-} + \ce{H2O}_{(l)} \rightleftharpoons \ce{HSO3}_{(aq)}^{-} + \ce{OH}_{(aq)}^{-}\) | Biru | Biru | Basa |
(2) | \(\ce{K3PO4}\) | \(\ce{PO4}_{(aq)}^{3-} + \ce{H2O}_{(l)} \rightleftharpoons \ce{HPO4}_{(aq)}^{2-} + \ce{OH}_{(aq)}^{-}\) | Biru | Merah | Asam |
(3) | \(\ce{CH3COONH4}\) | \(\ce{CH3COO}_{(aq)}^{-} + \ce{H2O}_{(l)} \rightleftharpoons \ce{CH3COOH}_{(aq)} + \ce{OH}_{(aq)}^{-}\)
\(\ce{NH4}_{(aq)}^{+} + \ce{H2O}_{(l)} \rightleftharpoons \ce{NH3}_{(aq)}^{-} + \ce{H3O}_{(aq)}^{+}\) |
Merah | Biru | Basa |
(4) | \(\ce{(NH4)2SO4}\) | \(\ce{NH4}_{(aq)}^{+} + \ce{H2O}_{(l)} \rightleftharpoons \ce{NH4OH}_{(aq)} + \ce{H}_{(aq)}^{+}\) | Merah | Merah | Asam |
Pasangan data garam terhidrolisis yang tepat adalah…
(A) (1) dan (2)
(B) (1) dan (3)
(C) (1) dan (4)
(D) (2) dan (3)
(E) (2) dan (4)
Jawaban: C
Soal 02
No | Larutan | Uji Lakmus Merah | Uji Lakmus Biru | Jenis Hidrolisis | Persamaan Reaksi Hidrolisis |
(1) | \(\ce{(NH4)2SO4}\) | merah | merah | \(\dotso\) | \(\ce{NH4}^{+} + \ce{H2O} \rightleftharpoons \ce{NH4OH} + \ce{H}^{+}\) |
(2) | \(\ce{NaF}\) | \(\dotso\) | biru | parsial | \(\ce{F}^{-} + \ce{H2O} \rightleftharpoons \ce{HF} + \ce{OH}^{-}\) |
(3) | \(\ce{HCOOK}\) | biru | biru | parsial | \(\dotso\) |
Data yang tepat untuk mengisi bagian titik-titik pada nomor (1), (2), dan (3) berturut-turut adalah…
(A) | Parsial | Merah | \(\ce{HCOO}^{-} + \ce{H2O} \rightleftharpoons \ce{OH}^{-} + \ce{HCOOH}\) |
(B) | Parsial | Biru | \(\ce{HCOO}^{-} + \ce{H2O} \rightleftharpoons \ce{OH}^{-} + \ce{HCOOH}\) |
(C) | Total | Biru | \(\ce{NH4OH} + \ce{HCOOH} \rightleftharpoons \ce{NH4}^{+} + \ce{HCOO}^{-} + \ce{H2O}\) |
(D) | Parsial | Merah | \(\ce{NH4}^{+} + \ce{H2O} \rightleftharpoons \ce{NH4OH} + \ce{H}^{+}\) |
(E) | Total | Merah | \(\ce{HCOO}^{-} + \ce{H2O} \rightleftharpoons \ce{HCOOH} + \ce{OH}^{-}\) |
Jawaban: B
Soal 03
Jika larutan 100 ml \(\ce{H2SO4}\) 0,1 M direaksikan dengan 0,8 gram \(\ce{NaOH}\), maka akan diperoleh…
(Ar Na = 23, O = 16, H = 1)
(1) Larutan garam terhidrolisis yang bersifat netral
(2) Larutan garam tak terhidrolisis
(3) larutan yang membirukan lakmus
(4) Larutan dengan pH = 7
Pernyataan di atas yang benar adalah…
(A) (1) dan (2)
(B) (1) dan (3)
(C) (2) dan (3)
(D) (2) dan (4)
(E) (3) dan (4)
Jawaban: D
\(\ce{H2SO4}\) | + | \(2\ce{NaOH}\) | \(\rightarrow\) | \(\ce{(Na)2SO4}\) | + | \(2\ce{H2O}\) | |
Mula-mula | 0,01 mol | 0,02 mol | – | – | |||
Reaksi | 0,01 mol | 0,02 mol | 0,01 mol | 0,02 mol | |||
Sisa | 0 | 0 | 0,01 mol |
Garam \(\ce{(Na)2SO4}\) berasal dari asam kuat dan basa kuat sehingga tidak terhidrolisis. pH larutan garamnya = 7 (netral)
Soal 04
Campuran berikut yang mengalami hidrolisis parsial dan bersifat asam adalah…
(A) 50 ml \(\ce{NaOH}\) 0,1 M + 50 ml \(\ce{HCl}\) 0,2 M
(B) 100 ml \(\ce{CH3COOH}\) 0,2 M + 50 ml \(\ce{KOH}\) 0,1 M
(C) 50 ml \(\ce{NH3}\) 0,2 M + 100 ml \(\ce{HCl}\) 0,1 M
(D) 100 ml \(\ce{NH4OH}\) 0,2 M + 100 ml \(\ce{H2SO4}\) 0,2 M
(E) 50 ml \(\ce{KOH}\) 0,2 M + 50 ml \(\ce{HCN}\) 0,2 M
Jawaban: C
Campuran yang mengalami hidrolisis parsial dan bersifat asam adalah campuran antara asam kuat dan basa lemah yang keduanya habis bereaksi (tidak ada sisa).
\(\ce{NH3}\) | + | \(\ce{HCl}\) | \(\rightarrow\) | \(\ce{NH4Cl}\) | |
Mula-mula | 10 mmol | 10 mmol | – | ||
Reaksi | 10 mmol | 10 mmol | 10 mmol | ||
Sisa | 0 | 0 | 10 mmol |
Reaksi hidrolisis:
\(\ce{NH4}^{+}_{(aq)} + \ce{H2O}_{(l)} \rightleftharpoons \ce{NH4OH}_{(aq)} + \ce{H}^{+}_{(aq)}\)
Soal 05
Natrium sianida (NaCN) dapat dibuat dengan mencampurkan 50 ml larutan NaOH 0,005 M dengan 50 ml larutan asam sianida 0,005 M. Senyawa tersebut dalam air akan terhidrolisis dengan pH larutan…
(Ka HCN = \(5 \times 10^{-10}, \sqrt{5} = 2,2\))
(A) \(2 \:-\: \log 1,5\)
(B) \(4 \:-\: \log 2,2\)
(C) \(10 \:-\: \log 5,0\)
(D) \(10 + \log 2,2\)
(E) \(12 + \log 1,5\)
Jawaban: D
\(\ce{NaOH}\) | + | \(\ce{HCN}\) | \(\rightarrow\) | \(\ce{NaCN}\) | + | \(\ce{H2O}\) | |
Mula-mula | 0,25 mmol | 0,25 mmol | – | – | |||
Reaksi | 0,25 mmol | 0,25 mmol | 0,25 mmol | 0,25 mmol | |||
Sisa | 0 | 0 | 0,25 mmol |
Reaksi hidrolisis:
\(\ce{CN}^{-}_{(aq)} + \ce{H2O}_{(l)} \rightleftharpoons \ce{HCN}_{(aq)} + \ce{OH}^{-}_{(aq)}\)
Larutan bersifat basa
\([\ce{OH}^{-}] = \sqrt{\dfrac{\text{Kw} \cdot [\ce{CN}^{-}]}{\text{Ka}}}\)
\([\ce{OH}^{-}] = \sqrt{\dfrac{10^{-14} \cdot \left(\dfrac{0,25}{100}\right)}{5 \times 10^{-10}}}\)
\([\ce{OH}^{-}] = \sqrt{\dfrac{10^{-14} \cdot 25 \times 10^{-4}}{5 \times 10^{-10}}}\)
\([\ce{OH}^{-}] = \sqrt{5 \times 10^{-8}}\)
\([\ce{OH}^{-}] = \sqrt{5} \times 10^{-4}\)
\(\text{pOH} = 4 \:-\: \log \sqrt{5}\)
\(\text{pOH} = 4 \:-\: \log 2,2\)
\(\text{pH} = 14\:-\: ( 4 \:-\: \log 2,2)\)
\(\text{pH} = 10 + \log 2,2\)
Soal 06
Campuran di bawah ini akan membentuk larutan yang terhidrolisis parsial dan bersifat basa adalah…
(A) 10 ml asam asetat 0,1 M dan 5 ml natrium hidroksida 0,4 M
(B) 10 ml larutan amonium hidroksida 0,1 M dan 5 ml asam klorida 0,1 M
(C) 10 ml gas amonia 0,2 M dan 5 ml asam klorida 0,4 M
(D) 10 ml asam asetat 0,2 M dan 10 ml gas amonia 0,1 M
(E) 10 ml asam formiat 0,1 M dan 10 ml kalium hidroksida 0,1 M
Jawaban: E
Campuran yang mengalami hidrolisis parsial dan bersifat basa adalah campuran antara basa kuat dan asam lemah yang keduanya habis bereaksi (tidak ada sisa).
\(\ce{HCOOH}\) | + | \(\ce{KOH}\) | \(\rightarrow\) | \(\ce{HCOOK}\) | + | \(\ce{H2O}\) | |
Mula-mula | 1 mmol | 1 mmol | – | – | |||
Reaksi | 1 mmol | 1 mmol | 1 mmol | 1 mmol | |||
Sisa | 0 | 0 | 1 mmol |
Reaksi hidrolisis:
\(\ce{HCOO}^{-}_{(aq)} + \ce{H2O}_{(l)} \rightleftharpoons \ce{HCOOH}_{(aq)} + \ce{OH}^{-}_{(aq)}\)
Soal 07
16,4 gram padatan natrium asetat dimasukkan ke dalam 200 ml air murni. Jika Ka \(\ce{CH3COOH} = 1 \times 10^{-5}, \text{ Kw} = 1 \times 10^{-14}\) dan Mr \(\ce{CH3COONa} = 82\). pH larutan yang terjadi adalah…
(A) 3
(B) 5,5
(C) 6,5
(D) 8,5
(E) 9,5
Jawaban: E
Reaksi hidrolisis:
\(\ce{CH3COO}^{-}_{(aq)} + \ce{H2O}_{(l)} \rightleftharpoons \ce{CH3COOH}_{(aq)} + \ce{OH}^{-}_{(aq)}\)
Larutan bersifat basa
\([\ce{OH}^{-}] = \sqrt{\dfrac{\text{Kw} \cdot [\ce{CH3COO}^{-}]}{\text{Ka}}}\)
\([\ce{OH}^{-}] = \sqrt{\dfrac{1 \times 10^{-14} \cdot \left(\dfrac{0,2 \text{ mol}}{0,2 \text{ liter}}\right)}{1 \times 10^{-5}}}\)
\([\ce{OH}^{-}] = \sqrt{1 \times 10^{-9}}\)
\([\ce{OH}^{-}] = 1 \times 10^{-4,5}\)
\(\text{pOH} = 4,5\)
\(\text{pH} = 14\:-\: ( 4,5)\)
\(\text{pH} = 9,5\)
Soal 08
Sebanyak 100 ml larutan \(\ce{H2SO4}\) 0,1 M direaksikan dengan 100 ml larutan \(\ce{NH3}\) 0,2 M. Jika \(\text{Kb} = 2 \times 10^{-5}\), maka pernyataan berikut yang salah adalah…
(log 5 = 0,7)
(A) \([\ce{H}^{+}]\) dalam campuran 0,4 M
(B) terbentuk larutan garam yang bersifat asam
(C) pH campuran adalah 5,15
(D) Tetapan hidrolisisnya adalah \(5\times 10^{-10}\)
(E) garam yang terbentuk terhidrolisis sebagian
Jawaban: A
\(\ce{H2SO4}\) | + | \(2\ce{NH3}\) | \(\rightarrow\) | \(\ce{(NH4)2SO4}\) | |
Mula-mula | 10 mmol | 20 mmol | – | ||
Reaksi | 10 mmol | 20 mmol | 10 mmol | ||
Sisa | 0 | 0 | 10 mmol |
Reaksi hidrolisis (hidrolisis parsial/sebagian)
\(\ce{NH4}^{+}_{(aq)} + \ce{H2O}_{(l)} \rightleftharpoons \ce{NH4OH}_{(aq)} + \ce{H}^{+}_{(aq)}\)
Larutan bersifat asam
\([\ce{H}^{+}] = \sqrt{\dfrac{\text{Kw} \cdot [\ce{NH4}^{+}]}{\text{Kb}}}\)
\([\ce{H}^{+}] = \sqrt{\dfrac{1 \times 10^{-14} \cdot \left(\dfrac{2 \times 10 \text{ mmol}}{200 \text{ ml}}\right)}{2 \times 10^{-5}}}\)
\([\ce{H}^{+}] = \sqrt{\dfrac{1}{2} \times 10^{-10}}\)
\([\ce{H}^{+}] = \sqrt{0,5\times 10^{-10}}\)
\([\ce{H}^{+}] = \sqrt{5\times 10^{-11}}\)
\([\ce{H}^{+}] = \sqrt{5} \times 10^{-5,5}\)
\(\text{pH} = 5,5 \:-\:\log \sqrt{5}\)
\(\text{pH} = 5,5 \:-\:\dfrac{1}{2}\log 5\)
\(\text{pH} = 5,15\)
Jadi, pH larutan yang terjadi adalah 5,15
Tetapan hidrolisis \(\text{Kh} = \dfrac{\text{Kw}}{\text{Kb}}\)
\(\text{Kh} = \dfrac{1 \times 10^{-14}}{2 \times 10^{-5}}\)
\(\text{Kh} = \dfrac{1}{2} \times 10^{-9}\)
\(\text{Kh} =0,5 \times 10^{-9}\)
\(\text{Kh} =5\times 10^{-10}\)