Question

The PKa of NH OH is 4. The PH of a solution prepared by mixing equal volumes of 0.01 M formic acid and 0.1 M, sodium formate is
(a) 3
(b) 4
(c) 5
(d) 7​

Answer 1

Answer:

option à is the right answer

Answer 2

Explanation:

Correct option is

C

39.6ml

Let V mL of 0.10M sodium formate solution should be added to 50ml of 0.05M formic acid to produce a buffer solution of pH 4.0.

pH=pKa+log

[HCOOH]

[HCOONa]

4.0=3.80+log

50×0.05

V×0.10

0.2=log0.04V

0.04V=1.585

V=39.6 mL.

Hence, the correct option is C

Option C is correct.