Roboguru

Larutan garam berikut ini yang mempunyai pH paling rendah adalah ....

Pertanyaan

Larutan garam berikut ini yang mempunyai pH paling rendah adalah ....
left parenthesis K subscript italic a space C H subscript 3 C O O H equals 1 comma 8 cross times 10 to the power of negative sign 5 end exponent comma space K subscript italic b space N H subscript 4 O H equals 1 comma 8 cross times 10 to the power of negative sign 5 end exponent right parenthesis 

  1. C H subscript 3 C O O Na 

  2. Al Cl subscript 3 

  3. K F 

  4. Na N O subscript 3 

  5. C H subscript 3 C O O N H subscript 4 

Pembahasan Soal:

Garam merupakan hasil reaksi antara asam dan basa. Garam terdiri dari 3 sifat yaitu:

  • Garam netral: terbentuk dari asam kuat dan basa kuat. open parentheses Na N O subscript 3 close parentheses 
  • Garam basa: terbentuk dari asam lemah dan basa kuat. open parentheses K F close parentheses dan open parentheses C H subscript 3 C O O Na close parentheses 
  • Garam asam: terbentuk dari asam kuat dan basa lemah. (Al Cl subscript 3).

Jika garam yang terbentuk dari asam lemah dan basa lemah maka sifatnya bergantung nilai K subscript italic a dan K subscript italic b nya. Jika:

  • K subscript italic a=K subscript italic b : garam netral (C H subscript 3 C O O N H subscript 4)
  • K subscript italic a>K subscript italic b : garam asam
  • K subscript italic a<K subscript italic b : garam basa

Garam yang memiliki nilai pH paling rendah adalah garam yang bersifat asam, yaitu terbentuk dari reaksi antara asam kuat dengan basa lemah yaitu garam Al Cl subscript 3. Untuk menentukan nilai pH nya dapat dihitung dengan rumus hidrolisis. 

Jadi, jawaban yang benar adalah B.

 

Pembahasan terverifikasi oleh Roboguru

Dijawab oleh:

F. Krisna

Mahasiswa/Alumni Institut Pertanian Bogor

Terakhir diupdate 07 Juni 2021

Roboguru sudah bisa jawab 91.4% pertanyaan dengan benar

Tapi Roboguru masih mau belajar. Menurut kamu pembahasan kali ini sudah membantu, belum?

Membantu

Kurang Membantu

Apakah pembahasan ini membantu?

Belum menemukan yang kamu cari?

Post pertanyaanmu ke Tanya Jawab, yuk

Mau Bertanya

Pertanyaan yang serupa

Perhatikan gambar di bawah ini!     Jika diketahui  dan . Tentukanlah pH dari masing-masing larutan garam tersebut!

Pembahasan Soal:

Garam merupakan hasil reaksi antara asam dan basa. Garam terdiri dari garam netral, garam asam, dan garam basa.

  1. Larutan begin mathsize 14px style Na Cl end style merupakan garam netral karena terbentuk dari reaksi asam kuat dan basa kuat. Nilai pH garam netral adalah 7.
  2. Larutan begin mathsize 14px style Na subscript 2 C O subscript 3 end style merupakan garam basa karena terbentuk dari basa kuat dan asam lemah. NIlai pH larutan tersebut ditentukan dengan perhitungan berikut.

    begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell open square brackets O H to the power of minus sign close square brackets end cell equals cell square root of K subscript italic w over K subscript italic a cross times end root open square brackets garam close square brackets end cell row blank equals cell square root of fraction numerator 10 to the power of negative sign 14 end exponent over denominator 4 comma 5 cross times 10 to the power of negative sign 7 end exponent end fraction cross times end root 10 to the power of negative sign 1 end exponent end cell row blank equals cell 4 comma 7 cross times 10 to the power of negative sign 5 end exponent end cell row blank blank blank row pOH equals cell negative sign log space 4 comma 7 cross times 10 to the power of negative sign 5 end exponent end cell row blank equals cell 5 minus sign log space 4 comma 7 end cell row blank blank blank row pH equals cell 14 minus sign pOH end cell row blank equals cell 14 minus sign left parenthesis 5 minus sign log space 4 comma 7 right parenthesis end cell row blank equals cell 9 plus log space 4 comma 7 end cell end table end style
     
  3. Larutan begin mathsize 14px style N H subscript 4 Cl end style merupakan garam asam karena terbentuk dari reaksi asam kuat dengan basa lemah. Nilai pH larutan tersebut ditentukan melalui perhitungan berikut.

    begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell open square brackets H to the power of plus sign close square brackets end cell equals cell square root of K subscript italic w over K subscript italic b cross times open square brackets garam close square brackets end root end cell row blank equals cell square root of fraction numerator 10 to the power of negative sign 14 end exponent over denominator 1 comma 8 cross times 10 to the power of negative sign 5 end exponent end fraction cross times 10 to the power of negative sign 1 end exponent end root end cell row blank equals cell 7 comma 4 cross times 10 to the power of negative sign 6 end exponent end cell row blank blank blank row pH equals cell negative sign log space 7 comma 4 cross times 10 to the power of negative sign 6 end exponent end cell row blank equals cell 6 minus sign log space 7 comma 4 end cell end table end style 
     

Jadi, jawaban yang benar adalah sesuai perhitungan di atas.

Roboguru

Larutan 0,1 M di bawah ini mempunyai pH paling tinggi, yaitu ...

Pembahasan Soal:

pH tinggi artinya pH basa (pH > 7).

  1. Na Cl = garam bersifat netral (pH = 7)
  2. K subscript 2 S O subscript 4 = garam bersifat netral (pH = 7)
  3. C H subscript 3 C O O Na = garam bersifat basa (pH > 7)
  4. C H subscript 3 C O O H = asam lemah (pH < 7)
  5. N H subscript 4 N O subscript 3 = garam bersifat asam (pH < 7)


Jadi, jawaban sesuai adalah C.space  

Roboguru

Perhatikan beberapa larutan garam berikut:       Diketahui harga  atau  asam dan basa lemah sebagai berikut.     Urutan derajat keasaman (pH) kelima garam tersebut dari yang paling kecil...

Pembahasan Soal:

1. Garam begin mathsize 14px style C H subscript 3 N H subscript 3 Cl end style terbentuk dari asam kuat dan basa lemah sehingga terjadi hidrolisis parsial.


begin mathsize 14px style open square brackets H to the power of plus sign close square brackets equals square root of K subscript w over K subscript b cross times open square brackets Garam close square brackets end root open square brackets H to the power of plus sign close square brackets equals square root of fraction numerator 10 to the power of negative sign 14 end exponent over denominator 3 comma 7 cross times 10 to the power of negative sign 4 end exponent end fraction cross times left square bracket 0 comma 1 space M right square bracket end root open square brackets H to the power of plus sign close square brackets equals 0 comma 6 cross times 10 to the power of negative sign 5 end exponent pH space space space equals minus sign log space open square brackets H to the power of plus sign close square brackets equals space minus sign log space 0 comma 6 cross times 10 to the power of negative sign 5 end exponent equals 5 comma 2 end style 


2. Garam begin mathsize 14px style N H subscript 4 Cl end style tebentuk dari asam kuat dan basa lemah sehingga terjadi hidrolisis parsial.


begin mathsize 14px style open square brackets H to the power of plus sign close square brackets equals square root of K subscript w over K subscript b cross times open square brackets Garam close square brackets end root open square brackets H to the power of plus sign close square brackets equals square root of fraction numerator 10 to the power of negative sign 14 end exponent over denominator 1 comma 8 cross times 10 to the power of negative sign 5 end exponent end fraction cross times left square bracket 0 comma 1 space M right square bracket end root open square brackets H to the power of plus sign close square brackets equals 0 comma 24 cross times 10 to the power of negative sign 5 end exponent pH space space space equals minus sign log space open square brackets H to the power of plus sign close square brackets equals space minus sign log space 0 comma 24 cross times 10 to the power of negative sign 5 end exponent equals 5 comma 6 end style 
 

3. Garam NaCl tebentuk dari asam kuat dan basa kuat sehingga pH larutan nya adalah 7.

4. Garam KCN terbentuk dari asam lemah dan basa kuat sehingga terjadi hidrolisis parsial.


begin mathsize 14px style open square brackets O H to the power of minus sign close square brackets equals square root of K subscript w over K subscript a cross times open square brackets Garam close square brackets end root open square brackets O H to the power of minus sign close square brackets equals square root of fraction numerator 10 to the power of negative sign 14 end exponent over denominator 4 comma 9 cross times 10 to the power of negative sign 10 end exponent end fraction cross times left square bracket 0 comma 1 space M right square bracket end root open square brackets O H to the power of minus sign close square brackets equals 0 comma 14 cross times 10 to the power of negative sign 2 end exponent pOH space space space equals minus sign log space open square brackets O H to the power of minus sign close square brackets equals space minus sign log space 0 comma 14 cross times 10 to the power of negative sign 2 end exponent equals 2 comma 85 pH space space space space space space equals space 14 minus sign pOH space space space equals 14 minus sign 2 comma 85 equals 11 comma 15 end style 

 

5. Garam NaClO terbentuk dari asam lemah dan basa kuat sehingga terjadi hidrolisis parsial.


begin mathsize 14px style open square brackets O H to the power of minus sign close square brackets equals square root of K subscript w over K subscript a cross times open square brackets Garam close square brackets end root open square brackets O H to the power of minus sign close square brackets equals square root of fraction numerator 10 to the power of negative sign 14 end exponent over denominator 3 comma 1 cross times 10 to the power of negative sign 8 end exponent end fraction cross times left square bracket 0 comma 1 space M right square bracket end root open square brackets O H to the power of minus sign close square brackets equals 0 comma 2 cross times 10 to the power of negative sign 3 end exponent pOH space space space equals minus sign log space open square brackets O H to the power of minus sign close square brackets equals space minus sign log space 0 comma 2 cross times 10 to the power of negative sign 3 end exponent equals 3 comma 7 pH space space space space space space equals space 14 minus sign pOH space space space equals 14 minus sign 3 comma 7 equals 10 comma 3 end style 
 

Urutan pH garam dari yang paling kecil adalah 1-2-3-5-4.

Jadi, jawaban yang paling tepat adalah B.undefined 

Roboguru

Tuliskan masing-masing tiga contoh garam yang bersifat asam, basa, dan netral beserta reaksi kesetimbangannya dalam air!

Pembahasan Soal:

Garam bersifat asam

N H subscript 4 Cl space rightwards harpoon over leftwards harpoon space N H subscript 4 to the power of plus sign space plus space Cl to the power of minus sign N H subscript 4 to the power of plus sign space plus space H subscript 2 O space rightwards harpoon over leftwards harpoon space N H subscript 4 O H space plus space H to the power of plus sign Cl to the power of minus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 

Al open parentheses N O subscript 3 close parentheses subscript 3 space rightwards harpoon over leftwards harpoon space Al to the power of 3 plus sign space plus space 3 N O subscript 3 to the power of minus sign Al to the power of 3 plus sign space plus space H subscript 2 O space rightwards harpoon over leftwards harpoon space Al open parentheses O H close parentheses subscript 3 space plus space H to the power of plus sign N O subscript 3 to the power of minus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 

N H subscript 4 N O subscript 3 space rightwards harpoon over leftwards harpoon space N H subscript 4 to the power of plus sign space plus space N O subscript 3 to the power of minus sign N H subscript 4 to the power of plus sign space plus space H subscript 2 O space rightwards harpoon over leftwards harpoon space N H subscript 4 O H space plus space H to the power of plus sign N O subscript 3 to the power of minus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 
 

Garam bersifat basa

C H subscript 3 C O O Na space rightwards harpoon over leftwards harpoon space C H subscript 3 C O O to the power of minus sign space plus space Na to the power of plus sign C H subscript 3 C O O to the power of minus sign space plus space H subscript 2 O space rightwards harpoon over leftwards harpoon space C H subscript 3 C O O H space plus space O H to the power of minus sign Na to the power of plus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 

K C N space rightwards harpoon over leftwards harpoon space K to the power of plus sign space plus space C N to the power of minus sign K to the power of plus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow C N to the power of minus sign space plus space H subscript 2 O space rightwards harpoon over leftwards harpoon space H C N space plus space O H to the power of minus sign 

Na F space rightwards harpoon over leftwards harpoon space Na to the power of plus sign space plus space F to the power of minus sign Na to the power of plus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow F to the power of minus sign space plus space H subscript 2 O space rightwards harpoon over leftwards harpoon space H F space plus space O H to the power of minus sign 
 

Garam bersifat netral

Na Cl space rightwards harpoon over leftwards harpoon space Na to the power of plus sign space plus space Cl to the power of minus sign Na to the power of plus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow Cl to the power of minus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 

Mg S O subscript 4 space rightwards harpoon over leftwards harpoon space Mg to the power of 2 plus sign space plus space S O subscript 4 to the power of 2 minus sign Mg to the power of 2 plus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow S O subscript 4 to the power of 2 minus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 

Ca Cl subscript 2 space rightwards harpoon over leftwards harpoon space Ca to the power of 2 plus sign space plus space 2 Cl to the power of minus sign Ca to the power of 2 plus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow Cl to the power of minus sign space plus space H subscript 2 O space up diagonal strike rightwards arrow 
 

Jadi, jawaban sesuai dengan uraian di atas.space  

Roboguru

Perhatikan beberapa larutan garam berikut!  1)   2)   3)   4)   5)   Diketahui harga Ka atau Kb asam dan basa lemah sebagai berikut. Asam atau Basa lemah Ka/Kb     ...

Pembahasan Soal:

Garam merupakan senyawa yang dihasilkan dari reaksi netralisasi antara larutan asam dan larutan basa. Garam dapat terbentuk dari 4 reaksi kimia. Reaksi kimianya sebagai berikut: 

  1. Garam dari asam kuat dan basa kuat, garam ini bersifat netral (pH = 7). 
  2. Garam dari asam kuat dan basa lemah, garam ini bersifat asam (pH <7).
  3. Garam dari basa kuat dan asam lemah, garam ini bersifat basa (pH >7).
  4. Garam dari asam lemah dan basa lemah, sifat asam/basa bergantung pada nilai Ka dan Kb dari senyawa tersebut.

Berikut adalah perhitungan larutan garam:

A. begin mathsize 14px style C H subscript 3 N H subscript 3 Cl space 0 comma 1 space M end style (Kb begin mathsize 14px style C H subscript 3 N H subscript 2 end style = begin mathsize 14px style 3 comma 7 x 10 to the power of negative 4 end exponent end style)

Error converting from MathML to accessible text.     

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row pH equals cell negative sign log left parenthesis 1 comma 64 space x 10 to the power of negative sign 6 end exponent right parenthesis end cell row blank equals cell 6 minus sign log space 1 comma 64 end cell row blank equals cell 5 comma 78 end cell end table end style 

 

B. begin mathsize 14px style N H subscript 4 Cl space 0 comma 1 space M end style (Kb=begin mathsize 14px style 1 comma 8 x 10 to the power of negative sign 5 end exponent end style)

Error converting from MathML to accessible text.    

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row pH equals cell negative sign log left parenthesis 7 comma 4 x 10 to the power of negative sign 6 end exponent right parenthesis end cell row blank equals cell 6 minus sign log space 7 comma 4 end cell row blank equals cell 5 comma 13 end cell end table end style 

   

C. begin mathsize 14px style Na Cl space 0 comma 1 space M end style 

NaCl berasal dari asam kuat dan basa kuat sehingga pH nya adalah 7.

 

D. begin mathsize 14px style K C N space 0 comma 1 space M end style (Ka begin mathsize 14px style H C N end style = begin mathsize 14px style 4 comma 9 x 10 to the power of negative 10 end exponent end style)

Error converting from MathML to accessible text. 

undefined   

  

E. begin mathsize 14px style Na Cl O space 0 comma 1 space M end style (Ka begin mathsize 14px style H Cl O end style = begin mathsize 14px style 3 comma 1 x 10 to the power of negative sign 8 end exponent end style)

Error converting from MathML to accessible text.  

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row pOH equals cell negative sign log left parenthesis 1 comma 79 x 10 to the power of negative sign 4 end exponent right parenthesis end cell row blank equals cell 4 minus sign log 1 comma 79 end cell row blank equals cell 3 comma 74 end cell row pH equals cell 14 minus sign 3 comma 74 end cell row blank equals cell 10 comma 26 end cell end table end style  

Berdasarkan perhitungan di atas, dapat disimpulkan bahwa urutan pH larutan dari yang paling kecil ke besar yaitu:

begin mathsize 14px style N H subscript 4 Cl space 0 comma 1 space M end style < begin mathsize 14px style C H subscript 3 N H subscript 3 Cl space 0 comma 1 space M end style < begin mathsize 14px style Na Cl space 0 comma 1 space M end style < begin mathsize 14px style Na Cl O space 0 comma 1 space M end style < begin mathsize 14px style K C N space 0 comma 1 space M end style 

atau secara berturut- turut nilai pH nya:

begin mathsize 14px style 5 comma 13 less than 5 comma 78 less than 7 less than 10 comma 26 less than 11 comma 16 end style .

Jadi, jawaban yang benar adalah C.

Roboguru

Roboguru sudah bisa jawab 91.4% pertanyaan dengan benar

Tapi Roboguru masih mau belajar. Menurut kamu pembahasan kali ini sudah membantu, belum?

Membantu

Kurang Membantu

Apakah pembahasan ini membantu?

Belum menemukan yang kamu cari?

Post pertanyaanmu ke Tanya Jawab, yuk

Mau Bertanya

RUANGGURU HQ

Jl. Dr. Saharjo No.161, Manggarai Selatan, Tebet, Kota Jakarta Selatan, Daerah Khusus Ibukota Jakarta 12860

Coba GRATIS Aplikasi Ruangguru

Produk Ruangguru

Produk Lainnya

Hubungi Kami

Ikuti Kami

©2021 Ruangguru. All Rights Reserved