Question

A solution has $H^{+}$ ion concentration $0.0005\, M$. Its $pOH$ is

• A. 8.279
• B. 12.285
• C. 10.699
• D. 13.335

Answer 1

Answer: (C)

10.699

Answer 2

$\left[H^{+}\right]=0.0005=5 \times 10^{-4}$ $\left[O H^{-}\right]\left[H^{+}\right]=10^{-14}$ $\left[O H^{-}\right] \times 5 \times 10^{-4}=10^{-14}$ $\left[O H^{-}\right]=\frac{10^{-14}}{5 \times 10^{-4}}=2 \times 10^{-11}$ $p O H=-\log \left(2 \times 10^{-11}\right)$ $=10.699$