Question

A beer has a pH of 4.30. What is the \[[{{H}_{3}}{{O}^{+}}]\]?
A. \[3.0\times {{10}^{-4}}\]
B. \[2.0\times {{10}^{-4}}\]
C. \[2.0\times {{10}^{-5}}\]
D. \[5.0\times {{10}^{-5}}\]

Answer 1

Hint: pH means potential of hydrogen or power of hydrogen. It is a scale used to specify the acidity or basicity of an aqueous solution.

Complete Step by step solution: The pH scale is a negative logarithm of hydronium ion concentration. Solutions with a pH less than 7 are acidic in nature and solutions with a pH greater than 7 are basic. Solutions with a pH of 7 at this temperature are neutral example distilled water. The neutral value of the pH depends on the temperature, The pH value can be less than 0 for very strong acids, or greater than 14 for very strong bases. pH is basically a line on which we find that at 7 neutral solutions are there and those substance which lies in the lower than 7 position are acids and those on the left side of scale i.e. having value greater than 7 are basic in nature also there acidity and basicity order can be seen by the value they represent on scale. Basic formula of pH is as shown:
\[pH=-\log {{[{{H}_{3}}O]}^{+}}\]
\[\log {{[{{H}_{3}}O]}^{+}}=-pH\]
In question pH of beer is given 4.30
\[\log {{[{{H}_{3}}O]}^{+}}=-4.30\]
\[\Rightarrow {{[{{H}_{3}}O]}^{+}}=anti\log (-4.30)\]
\[\Rightarrow {{[{{H}_{3}}O]}^{+}}=anti\log (0.70)\times {{10}^{-5}}\]
\[\Rightarrow {{[{{H}_{3}}O]}^{+}}=5.012\times {{10}^{-5}}\]

Hence option D is correct.

Note: Rather than pH value acid, bases or neutral can also be detected with the help of litmus paper and many other tests are performed to identify the characteristics of acid and bases. Generally acids contain \[{{H}^{+}}\] while bases contain \[O{{H}^{-}}\] ions.