Question

What is the $pH$ at equivalence point in the titration of $0.1 \,M \,CH _{3} COOH$ and $0.1 \,M \,NaOH ?\left( K _{a}\right.$ for acetic acid is $1.8 \times 10^{-5}$ )

• A. 7
• B. Between 7 and 8
• C. Between 8 and 9
• D. Between 6 and 7

Answer 1

Answer: (A)

For weak acid and strong base,
$p H=7+\frac{1}{2} p K_{a}+\frac{1}{2} \log C$
$ =7+\frac{4.74}{2}+\frac{1}{2} \log 10^{-1}$