Question

Normality of $\text{H}_2\text{SO}_4$ is}

• A. Molecular mass/1
• B. Molecular mass/2
• C. Molecular mass/4
• D. Molecular mass/0.5

Hint:

For monobasic acids (like \(\text{HCl}\) or \(\text{HNO}_3\)), equivalent weight = molecular weight. For dibasic acids (like \(\text{H}_2\text{SO}_4\) or oxalic acid), equivalent weight = molecular weight 2.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Normality (\(N\)) of an acid solution is defined as the number of gram equivalents of solute dissolved per liter of solution.
The equivalent weight of an acid depends on its molecular mass and its basicity (the number of replaceable hydrogen ions, \(\text{H}^+\), per molecule of acid).
Key Formula or Approach:
The relationship between Normality, Molarity (\(M\)), and basicity (or n-factor) is:
\[ \text{Normality (N)} = \text{Molarity (M)} \times \text{Basicity} \] The equivalent weight is calculated as:
\[ \text{Equivalent Weight} = \frac{\text{Molecular Mass}}{\text{Basicity}} \]

Step 2: Detailed Explanation:
Sulfuric acid (\(\text{H}_2\text{SO}_4\)) is a strong, dibasic mineral acid.
Each molecule of \(\text{H}_2\text{SO}_4\) can dissociate to release two protons:
\[ \text{H}_2\text{SO}_4 \rightarrow 2\text{H}^+ + \text{SO}_4^{2-} \] Because its basicity is \( 2 \), its equivalent weight is:
\[ \text{Equivalent Weight} = \frac{\text{Molecular Mass of }\text{H}_2\text{SO}_4}{2} \] The molecular mass of \(\text{H}_2\text{SO}_4\) is approximately \( 98\text{ g/mol} \), so its equivalent mass is \( \frac{98}{2} = 49\text{ g/eq} \).
A \( 1\text{ N} \) solution of \(\text{H}_2\text{SO}_4\) contains one gram equivalent (\( 49\text{ g} \)) of the acid per liter of solution.
Thus, the base unit of mass for calculating the normality of \(\text{H}_2\text{SO}_4\) is \(\text{Molecular mass}/2\).

Step 3: Final Answer:
The mass associated with the normality (equivalent mass) of \(\text{H}_2\text{SO}_4\) is Molecular mass/2.