Question

$0.16\mathrm{g}$ of dibasic acid requires $25\mathrm{mL}$ decimolar NaOH solution for complete neutralisation. The molecular mass of the acid is}

• A. 256
• B. 64
• C. 32
• D. 128

Hint:

For dibasic acid, n-factor = 2, equivalents of acid = equivalents of base.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
For dibasic acid, n-factor = 2, equivalents of acid = equivalents of base.
Step 2: Detailed Explanation:
Moles of NaOH = $0.1 \times \frac{25}{1000} = 0.0025$ mol. For dibasic acid, moles of acid = $\frac{0.0025}{2} = 0.00125$ mol. Molar mass = $\frac{0.16}{0.00125} = 128$ g/mol.
Step 3: Final Answer:
The molecular mass is 128.