Which of the following is/are correct for buffer solution?

Basic buffer will be effective within the pH range $({\text{pK}}_{\text{w}}-{\text{\hspace{0.17em}pK}}_{\text{b}}\text{\hspace{0.17em}±\hspace{0.17em}1})$

${\text{H}}_{\text{3}}{\text{PO}}_{\text{4}}{\text{\hspace{0.17em}+\hspace{0.17em}NaH}}_{\text{2}}{\text{PO}}_{\text{4}}$ is not a buffer solution 

Buffer behaves most effectively when the [Salt]/[Acid] ratio equal to one 

Acidic buffer will be effective within in the pH range $\left({\text{pK}}_{\text{a}}\text{\hspace{0.17em}±\hspace{0.17em}1}\right)$