Question

The pH of an aqueous solution having hydroxide ion concentration as $1\times 10^{-5}$ is

• A. 5
• B. 9
• C. 4.5
• D. 11

Answer 1

Answer: (B)

$\left[O{H}^{-}\right]=1\times 10^{-5}$
$pOH=-\log \left[O{H}^{-}\right]$
$=-\log \left[1\times 10^{-5}\right]$
$pOH=5pH+pOH=14$
$pH=14-pOH$
$14-5pH=9$