Question

When pH of a solution is $2$, the hydrogen ion concentration in $mol$ ${litre}^{-1}$ is:

• A. $1\times {10}^{-12}$
• B. $1\times {10}^{-2}$
• C. $1\times {10}^{-7}$
• D. $1\times {10}^{-4}$

Answer 1

Answer: (B)

$1\times {10}^{-2}$

Given that,

$pH=2$ for $HCl$ acid.

Relation between concentration of acid and pH is

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

Hence, option $B$ is correct.