Question

What is the $O{H}^{-}$ ion concentration for a solution with a pH of $10$ at ${25}^{\circ }C$?

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

Answer 1

Answer: (D)

${10}^{-4}M$

$pH=10$

$\therefore pOH=14-10=4[\because pH+pOH=14$ at ${25}^{o}C]$

$\therefore -\log \left[O{H}^{-}\right]=4$

$\therefore \left[O{H}^{-}\right]={10}^{-4}$ $M$

So, the $O{H}^{-}$ ion concentration for a solution with a $pH$ of $10$ at ${25}^{o}C$ is ${10}^{-4}$ $M$