Roboguru

Larutan  dengan konsentrasi tertentu mempunyai . Jika diketahui , konsentrasi larutan  sebesar....

Pertanyaan

Larutan undefined dengan konsentrasi tertentu mempunyai begin mathsize 14px style pH equals 10 plus log space 2 end style. Jika diketahui begin mathsize 14px style K subscript b equals 1 comma 8 cross times 10 to the power of negative sign 5 end exponent end style, konsentrasi larutan undefined sebesar....

  1. begin mathsize 14px style 0 comma 45 cross times 10 to the power of negative sign 4 end exponent end style 

  2. begin mathsize 14px style 2 comma 2 cross times 10 to the power of negative sign 4 end exponent end style 

  3. begin mathsize 14px style 0 comma 45 cross times 10 to the power of negative sign 3 end exponent end style 

  4. begin mathsize 14px style 2 comma 2 cross times 10 to the power of negative sign 3 end exponent end style 

  5. begin mathsize 14px style 4 comma 5 cross times 10 to the power of negative sign 3 end exponent end style 

Pembahasan Soal:

Larutan begin mathsize 14px style N H subscript 4 O H end style merupakan basa lemah sehingga untuk mencari konsentrasinya menggunakan perhitungan di bawah ini:

  1. Mencari pOH

    begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row blank blank cell pOH equals 14 minus sign pH equals 14 minus sign left parenthesis 10 plus log space 2 right parenthesis equals 4 minus sign log space 2 end cell end table end style
     
  2. Mencari begin mathsize 14px style open square brackets O H to the power of minus sign close square brackets end style

    begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row pOH equals cell negative sign space log space open square brackets O H to the power of minus sign close square brackets end cell row cell 4 minus sign log space 2 end cell equals cell negative sign space log space open square brackets O H to the power of minus sign close square brackets end cell row cell open square brackets O H to the power of minus sign close square brackets end cell equals cell 2 cross times 10 to the power of negative sign 4 end exponent end cell end table end style
     
  3. Mencari konsentrasi begin mathsize 14px style N H subscript 4 O H end style

    begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row blank blank end table table attributes columnalign right center left columnspacing 0px end attributes row blank blank cell open square brackets O H to the power of minus sign close square brackets equals square root of K subscript b cross times M subscript b end root 2 cross times 10 to the power of negative sign 4 end exponent equals square root of 1 comma 8 cross times 10 to the power of negative sign 5 end exponent cross times M subscript b end root fraction numerator 4 cross times 10 to the power of negative sign 8 end exponent over denominator 1 comma 8 cross times 10 to the power of negative sign 5 end exponent end fraction equals M subscript b 2 comma 22 cross times 10 to the power of negative sign 3 end exponent equals M subscript b end cell end table end style 

Jadi, jawaban yang benar adalah D.space 

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 05 Maret 2021

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