Roboguru

Sejumlah  dimasukkan ke dalam 500 mL air membentuk...

Sejumlah begin mathsize 14px style H subscript 3 P O subscript 4 end style dimasukkan ke dalam 500 mL air membentuk larutan dengan konsentrasi 0,15 M dan terurai menurut persamaan reaksi yang berlangsung dengan tahap berikut:

Tahap 1: begin mathsize 14px style H subscript 3 P O subscript 4 left parenthesis italic a italic q right parenthesis equilibrium H to the power of plus sign left parenthesis italic a italic q right parenthesis plus H subscript 2 P O subscript 4 to the power of 2 minus sign end exponent left parenthesis italic a italic q right parenthesis space K subscript a 1 end subscript equals 6 comma 0 cross times 10 to the power of minus sign cubed end style  

Tahap 2: begin mathsize 14px style H subscript 2 P O subscript 4 to the power of 2 minus sign end exponent left parenthesis italic a italic q right parenthesis equilibrium H to the power of plus sign left parenthesis italic a italic q right parenthesis plus H P O subscript 4 to the power of 2 minus sign end exponent left parenthesis italic a italic q right parenthesis space K subscript a 2 end subscript equals 6 comma 2 cross times 10 to the power of minus sign to the power of 8 end style  

Tahap 3: begin mathsize 14px style H P O subscript 4 to the power of minus sign left parenthesis italic a italic q right parenthesis equilibrium H to the power of plus sign left parenthesis italic a italic q right parenthesis plus P O subscript 4 to the power of negative sign 3 end exponent left parenthesis italic a italic q right parenthesis space K subscript a 3 end subscript equals 2 comma 2 cross times 10 to the power of negative sign 12 end exponent end style

Tentukan pH dari larutan asam begin mathsize 14px style H subscript 3 P O subscript 4 end style tersebut! (begin mathsize 14px style A subscript r space H equals 1 comma space P equals 31 comma space O equals 16 end style

Jawaban:

Jika diketahui tahap-tahap reaksi ionisasi asam lemah, maka pH larutan ditentukan dari reaksi dengan nilai begin mathsize 14px style K subscript a end style paling besar, yaitu reaksi pertama. 

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 a cross times M subscript a end root end cell row blank equals cell square root of 6 comma 0 cross times 10 to the power of negative sign 3 end exponent cross times 0 comma 15 end root end cell row blank equals cell square root of 0 comma 9 cross times 10 to the power of negative sign 3 end exponent end root end cell row blank equals cell square root of 9 cross times 10 to the power of negative sign 4 end exponent end root end cell row blank equals cell 3 cross times 10 to the power of negative sign 2 end exponent end cell row pH equals cell negative sign log space open square brackets H to the power of plus sign close square brackets end cell row blank equals cell negative sign log space 3 cross times 10 to the power of negative sign 2 end exponent end cell row blank equals cell 2 minus sign log space 3 end cell end table end style 

Jadi, pH larutan tersebut adalah 2 - log 3.

0

Ruangguru

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