First slide

Acidic buffer

Question

What amount of sodium propanoate should be added to one litre of an aqueous solution containing 0.02 mole of propanoic acid $(K_{a} = 1.0 \times 10^{- 5} at 25^{0} C)$ to obtain a buffer solution of pH 6

Moderate

A

0.1 M
B

0.2 M
C

0.3 M
D

1.3 M

Solution

Using the expression
$pH = {pK}_{a} + \log \frac{[Salt]}{[Acid]}$
we get, $6 = - \log (1.0 \times 10^{- 5}) + \log \frac{[Salt]}{[0.02 M]}$
which gives $6 = 5 + \log \frac{[Salt]}{[0.02 M]}$
or $\frac{[Salt]}{[0.02 M]} = 10 or [Salt] = 0.2 M$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App