Identify the correct route for the formation of phenyl benzoate, C6H5COOC6H5 (the ester in which the phenolic

NCERT Exemplar · Q4

Q. Identify the correct route for the formation of phenyl benzoate, C6H5COOC6H5 (the ester in which the phenolic oxygen of phenol is acylated by a benzoyl group).

(i) Phenol and benzoic acid in the presence of NaOH

(ii) Phenol and benzoyl chloride in the presence of pyridine

(iii) Phenol and benzoyl chloride in the presence of ZnCl2

(iv) Phenol and benzaldehyde in the presence of palladium

Ladakh CbseMCQ· 1mImportance★★★★★est

43% · 37/87 Questions

🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Concept understanding — Esterification

You already know that an acid and an alcohol can react. But why would they? And what do they make?

Think of a carboxylic acid as a molecule with a "sticky" end — the carboxyl group ( $-COOH$ ). That end has an -OH group of its own. An alcohol also has an -OH group. If you bring them together with a little help from a strong acid catalyst (like concentrated $H_2SO_4$ ), the -OH from the acid and the -H from the alcohol's -OH group can break off and join to form water. The two remaining fragments snap together, forming a new molecule: an ester.

So the reaction is a kind of condensation — two molecules join by losing a small molecule (water). The catalyst (acid) makes the acid's carbonyl carbon more reactive so the alcohol can attack it.

Note

The water comes from the acid's -OH and the alcohol's -H. The rest of the alcohol's oxygen stays in the ester.

Precise statement:

Esterification is the reversible, acid-catalyzed reaction between a carboxylic acid and an alcohol to produce an ester and water.

The general equation is:

R-COOH + R'-OH \xrightleftharpoons[H^+]{\text{heat}} R-COO-R' + H_2O

Here, $R$ and $R'$ are alkyl (or aryl) groups. The $R$ comes from the acid, the $R'$ from the alcohol. The ester link is $-COO-$ .

R-COOH + R'-OH \xrightleftharpoons[H^+]{\Delta} R-COO-R' + H_2O

Key exam points:

The reaction is reversible — the ester can be hydrolysed back to acid and alcohol (the reverse is called saponification when done with base).
Concentrated $H_2SO_4$ acts as both a catalyst and a dehydrating agent (it absorbs the water formed, shifting equilibrium toward products).
The reaction is slow at room temperature; heat is needed.
Esters have characteristic fruity smells — that's why this reaction is used in perfumes and flavourings. …

Start your 14-day free trial to unlock the full solution →

Phenyl benzoate, C6H5COO-C6H5, is the benzoate ester of phenol. It is made by benzoylating phenol with benzoyl chloride (C6H5COCl) using pyridine as the base. Phenol is too weak a nucleophile to esterify directly with benzoic acid, so option (ii) is correct.

Concept

Ester formation at a phenolic -OH is difficult by direct (Fischer) esterification because phenol is a poor nucleophile and the equilibrium is unfavourable. The practical route is acylation with an acid chloride, which is highly electrophilic.

Why this reagent

Benzoyl chloride reacts readily with the phenolic oxygen. A tertiary amine base (pyridine) is added to mop up the HCl produced and to keep the medium from becoming strongly acidic; this drives the reaction to completion (Schotten-Baumann conditions).

Reaction

C6H5OH + C6H5COCl --(pyridine)--> C6H5COOC6H5 + HCl

Why the distractors fail …

Start your 14-day free trial to unlock the full solution →

←Previous questionQ3 — The correct order of increasing acidic strength is _______. (i) Phenol…→Next questionQ5 — The reagent which does not react with both acetone and benzaldehyde is…

Q.Identify the correct route for the formation of phenyl benzoate, C6H5COOC6H5 (the ester in which the phenolic oxygen of phenol is acylated by a benzoyl group).

Concept understanding — Esterification

Concept

Why this reagent

Reaction

Why the distractors fail …

Method: Choosing the Correct Acylating Route for a Phenolic Ester (MCQ Elimination)

Core Concept

Steps

Q.Identify the correct route for the formation of phenyl benzoate, C6H5COOC6H5 (the ester in which the phenolic oxygen of phenol is acylated by a benzoyl group).

Concept

Why this reagent

Reaction

Why the distractors fail …

🎓Unlock everything free for 14 days

Unlock everything free for 14 days