Logo
Jeeify
NVAMediumJEE 2023Carboxylic Acids

JEE Chemistry 2023 Question with Solution

Number of compounds from the following which will not dissolve in cold NaHCO3\mathrm{NaHCO_3} and NaOH\mathrm{NaOH} solutions but will dissolve in hot NaOH\mathrm{NaOH} solution is .......

Seven aromatic compounds are shown, including benzoic acid derivatives, aromatic esters, a hydroxy ketone, a hydroxy aldehyde, and anisole-like structures for solubility comparison.

Answer

Correct answer:3

Step-by-step solution

Standard Method

Given: A set of aromatic compounds is provided.

Find: The number of compounds that do not dissolve in cold NaHCO3\mathrm{NaHCO_3} and cold NaOH\mathrm{NaOH} solutions, but do dissolve in hot NaOH\mathrm{NaOH} solution.

From the solution text, the compounds satisfying this condition are 2, 3, 7.

  • Carboxylic acid containing compounds dissolve in NaOH\mathrm{NaOH} and NaHCO3\mathrm{NaHCO_3}.
  • Phenol containing compounds react with NaOH\mathrm{NaOH}.
  • Esters dissolve in hot NaOH\mathrm{NaOH} due to hydrolysis.

Therefore, the number of such compounds is 33.

Common mistakes

  • Assuming all oxygen-containing compounds behave the same way in base is incorrect. Carboxylic acids dissolve in both NaOH\mathrm{NaOH} and NaHCO3\mathrm{NaHCO_3}, whereas esters generally require hot NaOH\mathrm{NaOH} for hydrolysis.

  • Treating phenols as soluble in NaHCO3\mathrm{NaHCO_3} is wrong. Phenols are not acidic enough to react with NaHCO3\mathrm{NaHCO_3}, though they can react with NaOH\mathrm{NaOH}.

  • Ignoring the word cold can lead to an incorrect count. Some compounds do not react in cold base but dissolve in hot NaOH\mathrm{NaOH} because hydrolysis becomes effective on heating.

Practice more Carboxylic Acids questions

Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.

Start free trialMore on Carboxylic Acids

Related questions