wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

To a solution of acetic acid, solid sodium acetate is added gradually. When x mole of salt is added, the pH has a certain value. If y mole of salt is added, the pH change by 0.6 units to the previous pH. What is the ratio of x and y?

Open in App
Solution

pH of a buffer solution of weak acid and its salt-
pH=pKa+log[salt][acid]
Let the volume of solution is V.
Therefore,
When x mole of salt is added-
Concentration of salt will be xV.
pH=pKa+log(xV)[acid].....(1)
When y mole of salt is added pH is changed by 0.6-
Concentration of salt will be yV.
pH+0.6=pKa+log(yV)[acid].....(2)
Subtracting equation (1) from (2), we have
(pH+0.6)pH=⎜ ⎜ ⎜pKa+log(yV)[acid]⎟ ⎟ ⎟⎜ ⎜ ⎜pKa+log(xV)[acid]⎟ ⎟ ⎟
0.6=pKa+log(yV)[acid]pKalog(xV)[acid]
0.6=logyx
yx=100.64
xy=14
Hence x:y=1:4.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
pH of a Solution
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon