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Sebanyak 100 mL  0,2 M dicampur dengan 100 mL laru...

Sebanyak 100 mL begin mathsize 14px style C H subscript 3 C O O H end style 0,2 M dicampur dengan 100 mL larutan begin mathsize 14px style Na O H end style 0,2 M. Jika begin mathsize 14px style K subscript a end style begin mathsize 14px style C H subscript 3 C O O H equals 1 cross times 10 to the power of negative sign 5 end exponent end style, maka pH larutan setelah dicampur adalah ....

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  5. 9undefined

Jawaban:

Langkah 1: Menghitung mol begin mathsize 14px style C H subscript bold 3 C O O H end style dan begin mathsize 14px style Na O H end style

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell mol subscript C H subscript 3 C O O H end subscript end cell equals cell V subscript C H subscript 3 C O O H end subscript cross times M subscript C H subscript 3 C O O H end subscript end cell row blank equals cell 100 space mL cross times 0 comma 2 space M end cell row blank equals cell 20 space mmol end cell end table end style

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell mol subscript NaOH end cell equals cell V subscript NaOH cross times M subscript NaOH end cell row blank equals cell 100 space mL cross times 0 comma 2 space M end cell row blank equals cell 20 space mmol end cell end table end style 


Langkah 2: membuat persamaan reaksi RMS


Langkah 3: menghitung konsentrasi garam begin mathsize 14px style C H subscript bold 3 C O O Na end style

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell open square brackets C H subscript 3 C O O Na close square brackets end cell equals cell n over V end cell row blank equals cell fraction numerator 20 space mmol over denominator 200 space mL end fraction end cell row blank equals cell 0 comma 1 space M end cell end table end style


Langkah 4: menghitung konsentrasi begin mathsize 14px style O H to the power of bold minus sign end style

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 w over K subscript a open square brackets C H subscript 3 C O O Na close square brackets end root end cell row blank equals cell square root of 10 to the power of negative sign 14 end exponent over 10 to the power of negative sign 5 end exponent left parenthesis 10 to the power of negative sign 1 end exponent right parenthesis end root end cell row blank equals cell square root of 10 to the power of negative sign 10 end exponent end root end cell row blank equals cell 10 to the power of negative sign 5 end exponent space M end cell end table end style 


Langkah 5: menghitung pH

begin mathsize 14px style 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 10 to the power of negative sign 5 end exponent end cell row blank equals 5 end table end style 

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


Dengan demikian, jawaban yang tepat adalah E.

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