Question

If $\left[O{H}^{-}\right]=5.0\times {10}^{-5}M$ then $pH$ will be:

• A. $5-\log 5$
• B. $9+\log 5$
• C. $\log 5-5$
• D. $\log 5-9$

Answer 1

The correct option is B $9+\log 5$

Given that,

$\left[O{H}^{-}\right]=5\times {10}^{-5}M$

$pOH=-log\left[O{H}^{-}\right]$

$pOH=-log[5\times {10}^{-5}]$

$pOH=5-log5$

Now, $pH=14-pOH$

$=14-(5-log5)$

$pH=9+log5$