Answer : The correct option is, [tex]1\times 10^{-6}M[/tex]
Explanation : Given,
The value of pH of HCl = 6
As we know that,
pH : It is defined as the negative logarithm of hydrogen ion or hydronium ion concentration.
The formula of pH is :
[tex]pH=-\log [H^+][/tex]
Now put all the given values in this formula, we get the concentration of hydrogen ion.
[tex]6=-\log [H^+][/tex]
[tex][H^+]=1\times 10^{-6}M[/tex]
Therefore, the concentration of hydrogen ion is, [tex]1\times 10^{-6}M[/tex]