Question

The hydronium ion concentration of wine is $1.4 \times {10^{ - 4}}$ M. What is the pH of the wine?
A.$2.15$
B.$3.85$
C.$3.15$
D.$4.14$

Answer 1

Hint:pH of a solution is the negative of base 10 logarithm of hydronium ion concentration in a solution. The concentration of hydronium ions in an aqueous solution can provide information about the acidic, basic, or neutral nature of a solution. For an acidic solution, pH is less than 7 and for a basic solution, pH is greater than 7. At room temperature, the pH of neutral water is equal to 7.

Complete step by step answer:
-To calculate the pH of an aqueous solution, you need to know the concentration of hydronium ions in moles per liter (molarity) of the solution.
-pH is then calculated using this expression
$pH = - {\log _{10}}\left[ {{H_3}{O^ + }} \right]$
Given,
-Hydronium ion concentration of wine or $\left[ {{H_3}{O^ + }} \right] = 1.4 \times {10^{ - 4}}M$
-Substituting this value in the above equation, we get
$pH = - {\log _{10}}\left[ {1.4 \times {{10}^{ - 4}}} \right]$
 $ = - {\log _{10}}1.4 - ( - 4){\log _{10}}10$
-We know ${\log _{10}}10 = 1$
 $ = 4 - {\log _{10}}1.4$
Value of ${\log _{10}}1.4 = 0.15$
-So $pH = 4 - 0.15$
  $ = 3.85$
So, the correct answer is an option (B).


Note: Molarity is defined as the number of moles of solute dissolved in one liter (or one cubic decimeter) of the solution.Molarity is also known as the molar concentration of a solution.