The $pH$ of an aqueous solution of $CH_3COONa$ of concentration $C \ M$ is given by:

• A
  $7 - \frac{1}{2} pK_a - \frac{1}{2} \log C$
• B
  $\frac{1}{2} pK_w + \frac{1}{2} pK_b + \frac{1}{2} \log C$
• C
  $\frac{1}{2} pK_w - \frac{1}{2} pK_b - \frac{1}{2} \log C$
• D
  $\frac{1}{2} pK_w + \frac{1}{2} pK_a + \frac{1}{2} \log C$