Question

The $pH$of water at $25^{o}C$ is nearly.

• A. 2
• B. 7
• C. 10
• D. 12

Answer 1

Answer: (B)

7

Answer 2

$\lbrack H^{+}\rbrack = \lbrack OH^{-}\rbrack$

$K_{w} = \lbrack H^{+}\rbrack\lbrack OH^{-}\rbrack = 10^{- 14}$

$\therefore\lbrack H^{+}\rbrack = 10^{- 7}$, $pH = - \log\lbrack H^{+}\rbrack = 7$.