Question

The pH of pure water at ${25}^{\circ }C$ is close to:

• A. 0
• B. 7
• C. 2
• D. 9

Answer 1

The correct option is B 7

For pure water at 25 ${}^{0}C$, $\left[H^{+}\right]=\left[O{H}^{-}\right]={10}^{-7}$.
Hence, $pH=-log\left[H^{+}\right]=-log{10}^{-7}=7$.