Question

pH of the solution containing 0.2 M CH3COOH and 0.1 M (CH3COO)2Sr is (pK, of CH3COOH = 4.7)
A) 4.4
B) 4.7
C) 5
D) 7​

Answer 1

Answer:

Answer will be 5

Explanation:

see attachment

Answer 2

The pH of the solution containing 0.2 M CH3COOH and 0.1 M (CH3COO)2Sr is A) 4.4

• PH is less than 7 for acids and more than 7 for the base.
• The formula for finding the Ph of salt of a weak acid and a weak base is:
• $Ph = Pka + log \frac{[salt]}{[acid]}$Concentration of salt (CH3COO)2Sr is 0.1M and the concentration of acid CH3COOH is 0.2 M.
• So,
• $Ph = Pka + log \frac{[(CH3COO)2Sr]}{[CH3COOH]}$
• $Ph = 4.7 + log \frac{0.1}{0.2} = 4.7 + \: log \frac{1}{2} = 4.7 - log \frac{2}{1} = 4.7 - 0.3010 = 4.4$
• Log 2 = 0.3010