Q56 / 180 · JIPMER 2016 · Chemistry
100 mL of a solution contains 2 g of acetic acid and 3 g of sodium acetate providing $K_a=1.8 \times 10^{-5}$, then choose the correct option.
- AThis solution is basic in nature
- Correct answerBThis solution is acidic in nature
- CThis solution is amphoteric in nature
- DThis solution is neutral in nature
Solution
We have the formula for pH
$\mathrm{pH}=-\log K_a+\log \frac{[\text { Salt }]}{[\text { Base }]}$
$[$ Salt $]=\frac{3 \times 1000}{82 \times 100} \mathrm{~mol} \mathrm{~L}^{-1}$
and
$\begin{aligned} {[\text { Acid }] } & =\frac{2 \times 1000}{60 \times 100} \mathrm{~mol} \mathrm{~L}^{-1} \\ \mathrm{pH} & =-\log 1.8 \times 10^{-5}+\log \frac{\frac{3 \times 1000}{82 \times 100}}{\frac{2 \times 1000}{60 \times 100}} \\ \mathrm{pH} & =4.7851\end{aligned}$
Hence, the correct answer is option: 'B'.