Aqueous solution of `HNO_(3),CH_(3),CH_(3)COOH`, and `CH_(3)COOK` of identical concentrations are given. The pair (s) of the solution which may form a buffer upon mixing is (are):

Options

A. `NaOH` and `CH_(3)COOH`
B. `HNO_(3)` and `CH_(3)COOK`
C. `CH_(3)COOH` and `CH_(3)COOK`
D. `HNO_(3)+CH_(3)COOH`

Answer

A, B, C

Explanation

Since concentrations are identical
If `V_(1)` is the volume of `CH_(3)COOH` and `V_(2)` is the volume of `NaOH`.
a. `{:(CH_(3)COOH+,NaOH),(V_(1),V_(2))]` Buffer is formed is `V_(1)gtV_(2)`
`{:(M_(1)~~,M_(2)):}`
`mmol of CH_(3)COOH(M_(1)V_(1)) lt "mmol of" NaOH (M_(2)V_(2))`. So `W_(A)` is left and buffer is formed.
b. `{:(CH_(3)COOK+,HNO_(3)rarr,CH_(3)COOH+KNO_(3)),(V_(1),V_(2),)]`
`{:(M_(1)~~,M_(2)):}`
Buffer is formed `V_(1) gt V_(2)`
mmol of salt `(CH_(3)COOK) gt mmol` of `HNO_(3)`. Some salt is hydrolysed to given `CH_(3)COOH` and some salt `CH_(3)COOK` is left to given buffer solution. `KNO_(3)` is completely ionised.
c. `{:(CH_(3)COOH+,CH_(3)COOK),(V_(1),V_(2))]`
Forms always a buffer. Mixture of `W_(A)` and salt of `W_(A)//S_(B)`.
d. `HNO_(3) +CH_(3)COOH]` It is mixture of `S_(A)` and `W_(A)`