Equilibrium Question 828
Question: What would be the pH of a solution obtained by mixing 5g of acetic acid and 7.5g of sodium acetate and making the volume equal to 500 mL- $ (K_{a}=1.75\times {10^{-5}},pK_{a}=4.76) $
Options:
A) $ pH=4.70 $
B) pH < 4.70
C) pH of solution will be equal to pH of acetic acid
D) 4.76 < pH < 5.0
Show Answer
Answer:
Correct Answer: D
Solution:
$ pH=pK_{a}+log\frac{[salt]}{[acid]} $
$ =4.76+log\frac{\frac{7.5}{100}}{\frac{5}{500}}=4.7+log1.5=4.87 $ Hence correct answer is $ 4.76<pH<5.0 $
