Question

$20\, mL\, 0.1( N )$ acetic acid is mixed with $10\, mL$ $0.1( N )$ solution of $NaOH$. The $pH$ of the resulting solution is $\left( p K_{a}\right.$ of acetic acid is $4.74$ )

• A. 3.74
• B. 4.74
• C. 5.74
• D. 6.74

Answer 1

Answer: (B)

4.74

Answer 2

From Henderson's equation,
$pH = p K_{a}+\log \frac{\left[ CH _{3} COONa \right]}{\left[ CH _{3} COOH \right]}$
$=4.74+\log \frac{1}{1}=4.74$