Question

Calculate the hydroxide concentration, if the solution has pH of $10$ at ${25}^{0}C$.

• A. ${10}^{-14}M$
• B. ${10}^{-10}M$
• C. ${10}^{-7}M$
• D. ${10}^{-4}M$
• E. ${10}^{-1}M$

Answer 1

Answer: (D)

${10}^{-4}M$

$pH+pOH=14$
$10+pOH=14$
$pOH=14-10=4$
$pOH=4=-log\left[O{H}^{-}\right]$
Hence, $\left[O{H}^{-}\right]={10}^{-4}$