Question

Bantu jawab ya ,,,soal tentang larutan buffer

Answer 1

1. Diket dan dit:
*n (NH4)2SO4 = 250 mL x 0,2 M = 50 mmol
*n NH3 = 250 mL x 0,1 M = 25 mmol
*pH = 9 --> [OH-] = 10^-5
*Kb ?

[OH-] = Kb x b/g
10^-5 = Kb x 25/50
Kb = 2 x 10^-5 (E)

2. Diket dan dit: 
*Massa CH3COOH = 6 gram
*Mr CH3COOH = 60 gram/mol
*n CH3COONa = 0,1 mol
*Ka = 10^-5
*pH ?

A. Mencari mol CH3COOH
--> n = g/Mr
= 6 /60
= 0,1 mol

B. Menghitung pH
[H+] = Ka x a/g
       = 10^-5 x 0,1 mol/0,1 mol
       = 10^-5

pH = 5 (B)