Question

What is the ${{H}^{+}}$ ion concentration of $5\times {{10}^{-3}}M$ ${{H}_{2}}C{{O}_{3}}$ solution having $10%$ dissociation:-
A. ${{10}^{-3}}$
B. ${{10}^{-2}}$
C. ${{10}^{-1}}$
D. $5\times {{10}^{-2}}$

Answer 1

Hint: We first discuss briefly about pH, that is, the potential of hydrogen or the power of hydrogen. Then we see how pH is calculated. And finally we find the ${{H}^{+}}$ ion concentration of $5\times {{10}^{-3}}M$ ${{H}_{2}}C{{O}_{3}}$ solution having $10%$ dissociation

Complete step by step answer:
In chemistry, The 'potential of hydrogen' or 'power of hydrogen' specifies the acidity or basicity of an aqueous solution using a scale known as PH scale. Acidic solutions, the solutions with higher concentrations of ${{H}^{+}}$ ions, are measured to have lower pH values than basic or alkaline solutions.

The pH scale is logarithmic and inversely indicates the concentration of hydrogen ions in the solution. This is because the formula used to calculate pH approximates the negative of the base 10 logarithms of the molar concentration[a] of hydrogen ions in the solution. More precisely, pH is the negative of the base 10 logarithm of the activity of the ${{H}^{+}}$ ion.

At 25 °C, solutions with a pH under 7 are acidic, and solutions with a pH more than 7 are base. s with a solution pH of 7 at this temperature are neutral (for example pure water). The neutral value of the pH relies upon the temperature, being lower than 7 if the temperature increments. The pH can be under 0 for solid acids, or more than 14 for extremely solid bases.

presently, let us consider
${{H}_{2}}C{{O}_{3}}\rightleftarrows 2{{H}^{+}}+CO_{3}^{2-}$
If ${{H}_{2}}C{{O}_{3}}$ is dissociated by $100%$ , then $5\times {{10}^{-3}}M$${{H}_{2}}C{{O}_{3}}$ will give $10\times {{10}^{-3}}M$ of ${{H}^{+}}$.
Now, as it is having $10%$ dissociation,
Concentration of ${{H}^{+}}$ ion = $\dfrac{10\times {{10}^{-3}}}{10}={{10}^{-3}}$ .
Therefore, ${{10}^{-3}}$ is the ${{H}^{+}}$ ion concentration of $5\times {{10}^{-3}}M$ ${{H}_{2}}C{{O}_{3}}$ solution having $10%$ dissociation.

So, the correct answer is Option A .

Note:
The pH scale is traceable to a set of standard solutions whose pH is set up by international agreement. Primary pH standard qualities are resolved to utilize a focus cell with transaction, by estimating the likely distinction between a hydrogen cathode and a standard electrode, for example, the silver chloride electrode. The pH of aqueous solutions can be measured with a glass electrode and a pH meter, or a shading evolving marker. measurement of pH are most important in chemistry, agronomy, medication, water treatment, and various different applications.