Question

Chemistry

Hitunglah Massa NaOH padat yang harus ditambahkan kedalam 100 ml Larutan CH3COOH 0,1 M ( ka = 10^(-5) ) agar diperoleh Larutan dengan pH = 5

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Answer 1

Verified answer

Materi : Asam Basa
Sub materi : Larutan Penyangga
Kata kunci : penyangga, buffer

NaOH + CH3COOH ---> CH3COONa + H2O

Gunakan rumus lar. penyangga asam

pH = 5 ---> [H+] = 10^-5 M

10^-5 = 10^-5 × [Asam]/[Garam]
[Asam] = [Garam]

Pd sistem larutan penyangga terdiri dari SISA asam lemah (CH3COOH) dgn garamnya (CH3COONa).

CH3COOH: 100 × 0.1 = 10 mmol

Diketahui jumlah mmol asam = jumlah mmol garamnya sehingga

[CH3COOH] = [CH3COONa]
10 - x = x
x = 5 mmol

NaOH: 5 mmol dlm 100 mL larutan tsb.

Massa NaOH yg ditambahkan:
5/100 × 40 = 2 gram


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