Question

pH of a salt solution of wak acid (pKa = 4) & weak base (pKb = 5) at 25�C is :

• A. 6.5
• B. 6
• C. 7
• D. 7.5

Answer 1

Answer: (A)

6.5

Answer 2

$pH=\frac{1}{2}\left(pKw + pka - pkb\right)=\frac{1}{2}\left(14 + 4 - 5\right) = 6.5$