The range of pH for acidic and basic buffer is where `K_(a)` and `K_(b)` are the acid base dissociation constants, respectively.

Options

A. form `pH=pK_(a)+-2 to pH=pK_(b)+-2`
B. from `pH=pK_(a)+1to pH=pK_(b)+1`
C. from `pH=pK_(a)+-1to pH=pK_(b)+-1`
D. from `pH=pK_(a)+1to pH=pK_(b)-1`

Answer

C

Explanation

When the pH of the acidic buffer does not differ greatly from the `pK_(a)` of the acid, the buffering action is the most efficient. This happens when the ration `[A^(-)]//[HA]` is between `0.1` and 10. Thus, `pH=pK_(a)+-1`.