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Jika ,  maka pH larutan  adalah ....

Pertanyaan

Jika begin mathsize 14px style K subscript a space open parentheses C H subscript 3 C O O H close parentheses space 1 cross times 10 to the power of negative sign 5 end exponent end style,  maka pH larutan begin mathsize 14px style C H subscript 3 C O O Na space 0 comma 1 space M end style adalah ....

  1. begin mathsize 14px style 9 end style 

  2. begin mathsize 14px style 13 end style 

  3. begin mathsize 14px style 7 end style 

  4. begin mathsize 14px style 11 end style 

  5. begin mathsize 14px style 3 end style 

Pembahasan Soal:

CH3COONa merupakan garam yang terbentuk dari reaksi asam lemah CH3COOH dan basa kuat NaOH Garam ini  terhidrolisis parsial karena hanya anion dari asam lemah yang bereaksi dengan air. Garam CH3COONa merupakan garam yang bersifat basa. Untuk mencari pH dari larutan garam tersebut terlebih dahulu kita menghitung konsentrasi OHdengan rumus:

 Error converting from MathML to accessible text. 

1. Menentukan konsentrasi anion garam CH3COO- 

C H subscript 3 C O O Na yields C H subscript 3 C O O to the power of minus sign and Na to the power of plus sign open square brackets C H subscript 3 C O O to the power of minus sign close square brackets double bond open square brackets C H subscript 3 C O O Na close square brackets open square brackets C H subscript 3 C O O to the power of minus sign close square brackets equals 0 comma 1 space M 

2. Menghitung konsentrasi OH-

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 fraction numerator 1 cross times 10 to the power of negative sign 14 end exponent over denominator 1 cross times 10 to the power of negative sign 5 end exponent end fraction cross times left parenthesis 0 comma 1 space M right parenthesis end root end cell row blank equals cell square root of fraction numerator 1 cross times 10 to the power of negative sign 14 end exponent over denominator 1 cross times 10 to the power of negative sign 5 end exponent end fraction cross times left parenthesis 1 cross times 10 to the power of negative sign 1 end exponent right parenthesis end root end cell row blank equals cell square root of 1 cross times 10 to the power of negative sign 10 end exponent end root end cell row blank equals cell 1 cross times 10 to the power of negative sign 5 end exponent space M end cell end table  

3. Menghitung nilai pOH

table attributes columnalign right center left columnspacing 0px end attributes row pOH equals cell negative sign log space open square brackets O H to the power of minus sign close square brackets end cell row blank equals cell negative sign log space left parenthesis 1 cross times 10 to the power of negative sign 5 end exponent right parenthesis end cell row blank equals cell 5 minus sign log space 1 end cell row blank equals 5 end table 

4. Menghitung nilai pH

table attributes columnalign right center left columnspacing 0px end attributes row pH equals cell 14 minus sign pOH end cell row blank equals cell 14 minus sign 5 end cell row blank equals 9 end table 


Jadi, jawaban yang benar adalah A.

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 03 Juni 2021

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