Answer:
D. 5
Explanation:
[tex]\mathbf{pH=-log_{10}[H^{+}]}[/tex]
The above formula is used to find pH of any solution. For that you require the concentration of [tex]\textrm{H}^{+}[/tex] or hydronium ion ([tex]\textrm{H}_{3}\textrm{O}^{+}[/tex]) in the solution. Concentration should be in molarity (M) to get the pH.
The concentration of [tex]\textrm{H}^{+}[/tex] ion is given as 0.00001 M or [tex]10^{-5}[/tex] M.
Substituting the value of [tex]\textrm{H}^{+}[/tex] ion in the formula:
[tex]\textrm{pH}=- \textrm{log}_{10}[10^{-5}][/tex]
[tex]\textrm{pH}=-(-5)\textrm{log}_{10}[10][/tex]
[tex]\textrm{pH}=-(-5)(1)[/tex]
[tex]\therefore\mathbf{pH=5}[/tex]
(NOTE : Some logarithmic properties
[tex]\mathbf{log_{b}(b)=1}\\ \mathbf{log_{b}(a^{c})=c \cdot log_{b}(a)}[/tex]
here 'b' is called the base of log and '[tex]\mathbf{a^{c}}[/tex]' is called dthe argument of log. In the solution the base is '10' and the argument is [tex]\mathbf{H^{+}}[/tex])
