Question

Assuming $HCl$ to be completely ionized the $pH$ of 0.2M molar aqueous solution of hydrochloric acid is approximately:

• A. 0.2
• B. 2
• C. 0.3
• D. 0.69

Answer 1

The correct option is D 0.69

Since $HCl$ is a strong acid, it will dissociate completely into it's ions at equilibrium.
The dissociation of HCl in aqueous medium is given by :$HCl\stackrel{+H_{2}O}{⟶}{H}_3{O}^{+}+C{l}^{-}Initial:C00Equilibrium:0CC$.
$[HCl{]}_{initially}=[H_3{O}^{+}{]}_{eqb.}=0.2MpH=-lo{g}_{10}\left[H_3{O}^{+}\right]=-lo{g}_{10}\left(0.2\right)=0.69pH=0.69$