9 mld 0,1 m ch3cooh (ka 10^-5 diencerkan 10 kali, kemudian d tambahkn larutan 10ml 0,1 m NaOH, maka larutan memiliki pH?
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Pertanyaan
9 mld 0,1 m ch3cooh (ka 10^-5 diencerkan 10 kali, kemudian d tambahkn larutan 10ml 0,1 m NaOH, maka larutan memiliki pH?
1 Jawaban
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1. Jawaban whongaliem
M1.V1 = M2 .V2
0,1 .9 = M2 .10 x 9
0,9 = M2 90
M2 = 0,9/90
M2 = 10^(-2)
mol CH3COOH = vol x M2
= 90 x 10^-2)
= 0,9 mm mol
mol NaOH = 10 ml x 0,1
= 1
= 1 mm mol
CH3COOH + NaOH ⇒ CH3COONa + H2O
mol CH3COONA = 1/1 x 0,9 mm mol
= 0,9 mm mol
= 9 x 10^(-2) mol
M CH3COONa = mol CH3COONa / Vol.total
= 9 x 10^(-2) / (90 + 10) ml
= 9 x 10^(-2) / (100 ml
= 9 x !0^(-2) / 0,1) liter
= 0,9 M
[OH-] = √{ Kw/Ka x M.garam}
= √{(10^-14 / 10^-5) x 0,9}
= √{ 10^-9 x 0,9}
= √(9 x 10^-10)
= 3 x 10^(-5)
POH = - log [OH-]
= - log (3 x 10^ - 5)
= 5 - log 3
PH = 14 - (5 - log 3)
= 9 + log 3