A weak acid after treatment with 12ml of 0.1m strong base BOH has a PH of 5. At the end point, the volume of same base required is 26.6ml Ka of acid is
1.8x10-15
8.12x10-6
1.8x10-6
18.2x10-5
As learnt in
Buffer Solutions -
The solutions which resist change in pH on dilution or with addition of small amounts of acid or alkali are called buffer solution.
- wherein
Many body fluids e.g. blood
Total milliequivalents of acid = milliequivalents of base
= 26.6 x 0.1 = 2.66
But the resultant mixture has HA left
The reaction is as follows:
HA + BOH BA + H2O
t=0 2.66 12 0 0
t1 1.46 0 1.2 1.2
Therefore for a buffer solution,
Option 1)
1.8x10-15
This answer is incorrect
Option 2)
8.12x10-6
This answer is correct
Option 3)
1.8x10-6
This answer is incorrect
Option 4)
18.2x10-5
This answer is incorrect