A mixture of a carboxylic acid and a phenol can often be separated by extracting with aqueous sodium bicarbonate and a suitable organic solvent. What difference in chemical properties of the carboxylic acid and the phenol make this separation possible?

Difference in acidity between carboxylic acid and phenol makes their separation possible by aqueous sodium bicarbonate.

Explanation:

of carboxylic acid lies in the range of 1.92 - 4.76

of phenol is 9.95

In sodium bicarbonate, acts as a strong base because it is derived from weak conjugate acid

Now, clearly, carboxylic acid will be preferably gives acid-base reaction with sodium bicarbonate to produce aqueous sodium carboxylate salt and phenol will remain as it is in a separate organic layer.

Unreacted phenol is then extracted with a suitable organic solvent by dissolving phenol in it.

Thus carboxylic acid and phenol can be separated by using aqueous sodium bicarbonate and a suitable organic solvent.

the answer is d.) potassium