Which of the following constitutes a buffer ?

Options

A. `HNO_(2)` and `NaNO_(2)`
B. `NaOH` and `NaCl`
C. `HNO_(3)` and `NH_(4)NO_(3)`
D. `HCl` and `KCl`

Answer

A

Explanation

A pair constituent with `HNO_(2)` and `NaNO_(2)` because `HNO_(2)` is weak acid and `NaNO_(2)` is a salt of weak acid `(HNO_(2))` with strong base (NaOH). Hence, it is an example of acidic buffer solution.