Question

The concentration of hydrogen ions in a ${10}^{-2}$ molar solution of hydrochloric acid can be taken to be ${10}^{-2}$ ions per litre. The logarithm of ${10}^{-2}$ is $2$. So the $pH$ of a ${10}^{-2}$ molar hydrochloride acid solution is:

• A. $-1/2$
• B. $-2$
• C. $2$
• D. $1/2$

Answer 1

Answer: (C)

$2$

Formula for the $pH$ is as follows:

$pH=-log\left[H^{+}\right]$

$pH=-log\left[{10}^{-2}\right]$

$=-(-2)$

Since, $\left[log\right[{10}^{-2}]=-2]$

$pH=2$

So answer is option $C$.