What is [H+] in mol/L of a solution that is 0.20 M in CH3COONa and 0.10 M in CH3COOH? Ka for CH3COOH = 1.8 10-5
- 3.5 10-4
- 1.1 10-5
- 1.8 10-5
- 9.0 10-6
Answer
(4) 9.0 10-6
Solution
The solution is an acidic buffer (CH3COOH + CH3COONa).
[H+] = Ka [Acid][Salt]
= 1.8 10-5 0.100.20
= 9.0 10-6 mol L-1
Answer: (4)