Which of the following combinations of solute would result in the formation of a buffer solution.
a. `CH_(3)COOH +NaOH` in
i. `1:1` mol ratio
ii. `2:1` mol ratio
iii. `1:2` mol ratio
b. `NH_(4)CI=NH_(3)`in
i. `1:1` mol ratio
ii. `2:1` mol ratio
iii. `1:2 `mol ratio
c. `HCI +NaCI`
d. `HCI +CH_(3)COOH`
e. `NaH +HCI`

Explanation

a. i. It will form salt of weak acid and strong base `(W_(A)//S_(B)) CH_(3)COONa`.
ii. It will form acidic buffer, since `1 mol` of weak acid will be left unreacted and `1mol` of `CH_(3)COONa` will be formed.
ii. `1mol` of `CH_(3) COONa` and `1mol` of `NaOH` is left.
b. (i),(ii), and (iii) all are basic buffers since in all cases it is a mixtu8re of salt of `W_(A)//S_(A) (NH_(4)CI)` and `W_(B) (NH_(3))`. Moreover, `NH_(4)CI` and `NH_(3)` do not react.
c. It is not buffer since it is a mixture of `S_(A)(HCI)` and salt of `S_(A)//S_(B) (NaCI)`.
d. It is not buffer since it is a mixture of `S_(A) (HCI)` and `S_(B) (NaOH)`.