Jika 50 mL larutan HCl 0,01 M memiliki pH yang sama dengan 5 liter larutan HA 0,1 M. Tentukan Ka asam HA.

Pertanyaan

Jika 50 mL larutan HCl 0,01 M memiliki pH yang sama dengan 5 liter larutan HA 0,1 M. Tentukan ${\mathrm K}_{\mathrm a}$ asam HA.

Pembahasan Soal:

Larutan HCl memiliki pH yang sama dengan larutan asam lemah HA yang menunjukkan bahwa $open square brackets H to the power of plus sign close square brackets$ kedua larutan sama.

$table attributes columnalign right center left columnspacing 0px end attributes row cell H Cl end cell rightwards arrow cell H to the power of plus sign and Cl to the power of minus sign space left parenthesis a space colon space 1 right parenthesis end cell row blank blank blank row cell open square brackets H to the power of plus sign close square brackets space H Cl end cell equals cell a cross times M end cell row blank equals cell 1 cross times 0 comma 01 end cell row blank equals cell 10 to the power of negative sign 2 end exponent end cell row blank blank blank row cell open square brackets H to the power of plus sign close square brackets space HA end cell equals cell open square brackets H to the power of plus sign close square brackets space H Cl end cell row blank equals cell 10 to the power of negative sign 2 end exponent end cell row cell open square brackets H to the power of plus sign close square brackets end cell equals cell square root of K subscript a cross times M end root end cell row cell K subscript a space HA end cell equals cell open square brackets H to the power of plus sign close square brackets squared over M end cell row blank equals cell fraction numerator left parenthesis 10 to the power of negative sign 2 end exponent right parenthesis squared over denominator 0 comma 1 end fraction end cell row blank equals cell 10 to the power of negative sign 4 end exponent over 10 to the power of negative sign 1 end exponent end cell row blank equals cell 10 to the power of negative sign 3 end exponent end cell end table$

Jadi, $K subscript a$ asam HA adalah $10 to the power of negative sign 3 end exponent$ .

Pembahasan terverifikasi oleh Roboguru

Dijawab oleh:

F. MT

Mahasiswa/Alumni Universitas Negeri Medan

Terakhir diupdate 06 Oktober 2021