Aqueous solutions of `HNO_(3), KOH, CH_(3)COOH`,and `CH_(3)COONa` of identical concentrations are provided. The pair (s) of solution which form a buffer upon mixing is// are

Options

A. `HNO_(3)` and `CH_(3)COOH`
B. `KOH` and `CH_(3)COONa`
C. `HNO_(3)` and `CH_(3)COONa`
D. `CH_(3)COOH` and `CH_(3)COONa`

Answer

C, D

Explanation

a. Not buffer since it is a mixture of `S_(A)` and `W_(A)`.
b. Not buffer sinxce it is a mixture of `S_(B)` and salt of `W_(A)//S_(B)`.
c. It is an acidic buffer. Since some of `HNO_(3)` will react with `CH_(3)COONa` to produce weak acid and some `CH_(3)COONa` to produce weal acid and some `CH_(3)COONa` will be left. So buffer is formed.
`{:(,HNO_(3)+,CH_(3)COONararr,NaNO_(3)+,CH_(3)COOH),("Initial",x,y,0,0),("Final",-,(y-x),(y-x),(y-x)):}`
d. It is an acidic buffer (mixture of `W_(A)` and salt of `W_(A)//S_(B))`