Question

Assertion :In the titration of $N{a}_{2}C{O}_3$ with $HCl$ using methyl orange indicator, the volume required at the equivalence point is twice that of the acid required using phenolphthalein indicator. Reason: Two moles of HCl are required for the complete neutralization of one mole of $N{a}_{2}C{O}_3$.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Methyl orange changes colour in the pH range $3.0$ to $4.4$ when only one mole of $HCl$ reacts with one mole of sodium carbonate.
Phenolphthalein changes colour in the pH range of $8.0$ to $9.8$ when one mole of sodium carbonate is completely neutralized with two moles of $HCl$.