Phenol is converted into P by CHCl3/NaOH followed by H3O+ (major ortho product), and into Q by heating its sodium salt with CO2 at 4-7 atm and 400 K followed by H3O+. Which single test distinguishes P from Q?

neutral FeCl3 solution (violet colour)

MolSynapse / Question bank / Alcohols, Phenols and Ethers / Distinguishing tests

JEE Advanced levelSingle correct optionDifficulty 3 of 3ap050

Phenol is converted into P by $CHCl X_{3}$ / $NaOH$ followed by $H X_{3} O X^{+}$ (major ortho product), and into Q by heating its sodium salt with $CO X_{2}$ at 4-7 atm and 400 K followed by $H X_{3} O X^{+}$ . Which single test distinguishes P from Q?

Aneutral $FeCl X_{3}$ solution (violet colour)
Baqueous $NaHCO X_{3}$ (effervescence)
Csodium metal ( $H X_{2}$ evolution)
Daqueous $NaOH$ (dissolution)

Answer: B

P is 2-hydroxybenzaldehyde (Reimer-Tiemann) and Q is 2-hydroxybenzoic acid (Kolbe-Schmidt). Both have a phenolic OH, so both give a violet colour with

FeCl X_{3}

, react with sodium and dissolve in

NaOH

. Only the carboxylic acid Q liberates

CO X_{2}

from

NaHCO X_{3}

Practice Alcohols, Phenols and Ethers More on Distinguishing tests

Previous questionNext question

Phenol is converted into P by CHClX3​/NaOH followed by HX3​OX+ (major ortho product), and into Q by heating its sodium salt with COX2​ at 4-7 atm and 400 K followed by HX3​OX+. Which single test distinguishes P from Q?

Answer: B

More questions on Distinguishing tests

Phenol is converted into P by $CHCl X_{3}$ / $NaOH$ followed by $H X_{3} O X^{+}$ (major ortho product), and into Q by heating its sodium salt with $CO X_{2}$ at 4-7 atm and 400 K followed by $H X_{3} O X^{+}$ . Which single test distinguishes P from Q?