Question

Identify the compound ‘X’?

• A. Toluidine
• B. Benzamide
• C. Para-Cresol
• D. None of these

Answer 1

The correct option is C

Para-Cresol

In the given question, if ‘X’ is a base, then it will be soluble in acid, but in the above question, the compound does not react with both a strong base i.e. sodium hydroxide as well as a weak base which is sodium bicarbonate and gives insoluble compounds.

The explanation for the Correct answer:

Option (C): The compound ‘X’ is Para-Cresol that is a weak acid that is insoluble in water.

1. Para-cresol is insoluble in water, 5% $\mathrm{HCl}$, and 10% ${\mathrm{NaHCO}}_3$ but soluble in 10% $\mathrm{NaOH}$.
2. $\mathrm{NaOH}$ abstracts proton from the hydroxyl group ($-\mathrm{OH}$) attached to para-cresol.
3. M-cresol is a phenol that is insoluble in water but it is soluble only to a lesser extent.
4. This is because it is an organic molecule and does not dissolve particularly well in water.
5. It is insoluble in acidic solution ($\mathrm{HCl}$) because the $\mathrm{OH}$ group does not dissociate.
6. It is soluble in $\mathrm{NaOH}$ solution. This is because phenol is acidic and because of this property, it dissolves in $\mathrm{NaOH}$ to form Sodium phenoxide.
7. The group should be base sensitive means it has acidic –H because it is soluble in 10% $\mathrm{NaOH}$ and it should be less acidic than ${\mathrm{H}}_3{\mathrm{CO}}_3$ because it is not soluble in ${\mathrm{NaHCO}}_3$.

The explanation for the wrong option:

Option (A): Toluidine is having an amine group and therefore is a base and not soluble in $\mathrm{NaOH}$ and 10% ${\mathrm{NaHCO}}_3$.

Option (B): Benzamide has an amide group which is also a base and not soluble in $\mathrm{NaOH}$ and 10% ${\mathrm{NaHCO}}_3$.

Hence, the correct answer is an option (C).