Question

A $0.001$ $M$ solution of which of the following has a hydrogen ion concentration of $1\times {10}^{-3}$ $M$?

• A. $H{C}_2{H}_3{O}_2$
• B. $HCl$
• C. $NaH{CO}_3$
• D. $NaH$
• E. $NaOH$

Answer 1

Answer: (B)

$HCl$

A $0.001M$ of $HCl$ has a hydrogen ion concentration of $1\times {10}^{-3}$ molar.
$HCl$ is a strong acid. It completely dissociates in an aqueous medium to provide hydrogen ions. Hence, the concentration of $HCl$ is equal to hydrogen ion concentration. The compounds in other options are either weak acids or bases. Hence, they cannot provide a solution with hydrogen ion concentration equal to the concentration of these compound.