Question

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

• A. Acidic buffer will be effective within in the $pH$ range $\left( p K_a \pm 1\right)$
• B. Basic buffer will be effective within the $pH$ range $\left( p K_w- p K_b \pm 1\right)$
• C. $H _3 PO _4+ NaH _2 PO _4$ is not a buffer solution
• D. Buffers behave most effectively when the [Salt]/[Acid] ratio equal to 1

Answer 1

Answer: (A), (B), (D)

For acidic buffer, buffer capacity is maximum at
$pH = p K_a$ and for basic buffer, it is maximum at
$pH = p K_w- p K_b$. Buffer is always effective within a $pH$ range of $1$ with respect to the $pH$ at maximum buffer capacity
$H _3 PO _4+ H _2 PO _4^{\ominus}$ is a buffer solution