Question

Calculate the ph of hydronium ions in a 0.000 01 M solution of the strong acid HI.

Answer 1

Answer:

D. 5

Explanation:

$\mathbf{pH=-log_{10}[H^{+}]}$

The above formula is used to find pH of any solution. For that you require the concentration of $\textrm{H}^{+}$ or hydronium ion ($\textrm{H}_{3}\textrm{O}^{+}$) in the solution. Concentration should be in molarity (M) to get the pH.

The concentration of $\textrm{H}^{+}$ ion is given as 0.00001 M or $10^{-5}$ M.

Substituting the value of $\textrm{H}^{+}$ ion in the formula:

$\textrm{pH}=- \textrm{log}_{10}[10^{-5}]$

$\textrm{pH}=-(-5)\textrm{log}_{10}[10]$

$\textrm{pH}=-(-5)(1)$

$\therefore\mathbf{pH=5}$

(NOTE : Some logarithmic properties

$\mathbf{log_{b}(b)=1}\\ \mathbf{log_{b}(a^{c})=c \cdot log_{b}(a)}$

here 'b' is called the base of log and '$\mathbf{a^{c}}$' is called dthe argument of log. In the solution the base is '10' and the argument is $\mathbf{H^{+}}$)