Question

A given weak acid $(0.01M)$ has $p{K}_a=6$ The $pH$ of the solution is____.

Answer 1

Answer: 4

$pH=-\log \sqrt{C{K}_a}=-\frac{1}{2}\left[\log C+\log K_a\right]$

$=\frac{1}{2}\left[-\log C-\log K_a\right]=\frac{1}{2}[-\log (0.01)+6]=4$