Question
The $$pH$$ value of a $$10$$ $$M$$ solution of $$HCl$$ is
A.
less than 0
B.
equal to 0
C.
equal to 1
D.
equal to 2
Answer :
less than 0
Solution :
$$HCl\left( {aq} \right) \to {H^ + }\left( {aq} \right) + C{l^ - }\left( {aq} \right)$$ $$\left[ {S = \sqrt {{K_{sp}}} } \right]$$
$$\eqalign{
& \,\,\,\,\,\,\,\left[ {HCl} \right] = 10M \cr
& \Rightarrow \left[ {{H^ + }} \right] = 10\,mol/L \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,pH = - {\text{log}}\left[ {{H^ + }} \right] \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = - {\text{log}}\,10 \cr} $$
$$ = - 1,\,{\text{so}}\,{\text{the}}\,pH\,{\text{is less than zero}}{\text{.}}$$