Which of the following is (are) correct for buffer solution?

Options

A. Acidic buffer will be effective within in the `pH` range `(pK_(a) +-1)`.
B. Basic buffer will be effective within the `pH` range `(pK_(w)-pK_(b)+-1)`.
C. `H_(3)PO_(4)+NaH_(2)PO_(4)`is not a buffer solution.
D. Buffers behave most effectively when the `["Salt"]//["Acid"]`

Answer

A, B, D

Explanation

For acidic buffer, buffer capacity is maximum at `pH = pK_(a)` and for basic buffer, it is maximum at `pH = pK_(w) - pK_(b)`. Buffer is always effective withn a `pH` range of `1` with respect to the `pH` at maximum buffer capacity.
`H_(3)PO_(4) +H_(2)PO_(4)^(Theta)` is a buffer solution.