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Test: Aldol Condensation - NEET MCQ


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27 Questions MCQ Test Chemistry Class 12 - Test: Aldol Condensation

Test: Aldol Condensation for NEET 2024 is part of Chemistry Class 12 preparation. The Test: Aldol Condensation questions and answers have been prepared according to the NEET exam syllabus.The Test: Aldol Condensation MCQs are made for NEET 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Aldol Condensation below.
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Test: Aldol Condensation - Question 1

Only One Option Correct Type

Direction (Q. Nos. 1-10) This section contains 10 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE is correct.

Q. 

Which is the major product in the following reaction?

Detailed Solution for Test: Aldol Condensation - Question 1

Test: Aldol Condensation - Question 2

Consider the following reaction,

Q. 

Which of the labeiled C—C bond formation is not possible in the above reaction? 

Detailed Solution for Test: Aldol Condensation - Question 2

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Test: Aldol Condensation - Question 3

In a mixed aldoi condensation with ethanal as one aidehyde, which other from the following is expected to give maximum yield of cross condensation product?

Detailed Solution for Test: Aldol Condensation - Question 3

Nucleophilic addition at carbonyl carbon of cyclopropane releases angle strain.

Test: Aldol Condensation - Question 4

In the following reaction,

The major organic product is 

Detailed Solution for Test: Aldol Condensation - Question 4

Test: Aldol Condensation - Question 5

Consider the following aldol condensation reaction,

Q.

The nucleophile is

Detailed Solution for Test: Aldol Condensation - Question 5

In acid catalysed aldo! condensation, enol acts as a nucleophile.

Test: Aldol Condensation - Question 6

In the following reaction,

Q. 

The major final product is

Detailed Solution for Test: Aldol Condensation - Question 6


Repeated aidol condensation occur due to very high reactivity of formaldehyde towards nucleophile.

Test: Aldol Condensation - Question 7

Identify the starting reagent needed to make the following compound by mixed aldol condensation.

Detailed Solution for Test: Aldol Condensation - Question 7


Test: Aldol Condensation - Question 8

The incorrect statement regarding aldol condensation is

Detailed Solution for Test: Aldol Condensation - Question 8

Enolate is formed in first fast step which undergo nucleophilic addition in second slow step.

Test: Aldol Condensation - Question 9

Which of the following could result as a product in the aldol condensation reaction?

Detailed Solution for Test: Aldol Condensation - Question 9


It is an α, β-unsaturated ketone which can be formed in an aldol condensation followed by dehydration.

Test: Aldol Condensation - Question 10

What is the major final product of the following sequence of reaction?

Detailed Solution for Test: Aldol Condensation - Question 10

*Multiple options can be correct
Test: Aldol Condensation - Question 11

One or More than One Options Correct Type

Direction (Q. Nos. 11-15) This section contains 5 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THAN ONE are correct.

Q. 

Successful mixed aldol condensation will be favoured 

Detailed Solution for Test: Aldol Condensation - Question 11

For successful mixed aldol condensation to be favored, the correct conditions should ensure that one carbonyl component acts as a nucleophile while the other acts as an electrophile. Here's the analysis of each option:

(a) Treatment of electrophilic carbonyl component with a stoichiometric strong base before the addition of the pre-nucleophilic carbonyl component

  • This would likely deprotonate the electrophilic carbonyl component, making it a poor electrophile and favoring side reactions. This is not favorable for a successful mixed aldol reaction.
    (Incorrect)

(b) Treatment of mixture of electrophilic carbonyl component and pre-nucleophilic component with stoichiometric strong base

  • This could result in deprotonation on both components, leading to a mixture of products and possibly side reactions.
    (Incorrect)

(c) Continuous removal of aldol product from the reaction mixture

  • Removing the aldol product shifts the equilibrium towards product formation, which is a beneficial condition for successful mixed aldol condensation.
    (Correct)

(d) Treatment of pre-nucleophilic carbonyl component with stoichiometric strong base prior to the addition of electrophilic carbonyl component

  • This ensures that the pre-nucleophilic component forms an enolate, which can then attack the electrophilic carbonyl component without side reactions, favoring a successful aldol condensation.
    (Correct)

Final Answer:

(c) and (d) are correct choices.

*Multiple options can be correct
Test: Aldol Condensation - Question 12

Which of the following is/are true regarding aldol condensation ?

Detailed Solution for Test: Aldol Condensation - Question 12

Both acid and base catalyses aldol reaction. In aldol reaction , a new α - β C—C bond is always formed . α - H is lost in first fast step, hence both CH3CHO and CD3CHO react at the same rate.

*Multiple options can be correct
Test: Aldol Condensation - Question 13

Which of the following indicated carbon-carbon bond can be formed via intramolecular aldoi condensation of a dicarbonyl compound?

Detailed Solution for Test: Aldol Condensation - Question 13

In aldol reaction as α-β C—C bond is always formed.

*Multiple options can be correct
Test: Aldol Condensation - Question 14

Which compound (s) below can react via an intramolecular aldol condensation to give a six membered ring?

Detailed Solution for Test: Aldol Condensation - Question 14

All of these react in aldol reaction giving six-membered ring via intramolecular reaction.
Option (b) gives five and seven membered ring intramolecular aldol condensation.

*Multiple options can be correct
Test: Aldol Condensation - Question 15

What is(are) true about the following aldoi reaction?

Detailed Solution for Test: Aldol Condensation - Question 15


Also, the starting compound has three different types of α-H, three different aldols can be formed in principle. If a pure enantiomer of starting compound is taken, a pair of diastereomers of aldol would be formed.

Test: Aldol Condensation - Question 16

Statement Type

Direction (Q. Nos. 16-19) This section is based on Statement I and Statement II. Select the correct answer from the codes given below.

Q. 

Statement I : In aldol condensation, enoiates are nucleophilic and reversibly attack the carbonyl carbon of aldehyde or ketone in the aldoi condensation.

Statement II : An aldoi on refluxing with dilute base gives back the carbonyl compound.

Detailed Solution for Test: Aldol Condensation - Question 16

Reversibility of aldol into carbonyls establishes that carbanion nucleophile is formed in first fast reversible step.

Test: Aldol Condensation - Question 17

Statement I : When a mixture of ethanal and propanal is treated with aqueous Na2CO3, four aldol (excluding stereoisomers) are formed.
Statement II : In mixed aldol condensation, two self and two cross condensation products are always formed.

Detailed Solution for Test: Aldol Condensation - Question 17

It would be true only if both carbonyls are capable of forming enolates, i.e. possesses α-H

Test: Aldol Condensation - Question 18

Statement I : When   is treated with dilute base.
  is formed.

Statement II : In the given compound, γ-H is most acidic, forms the required enolate.

Detailed Solution for Test: Aldol Condensation - Question 18

Test: Aldol Condensation - Question 19

Statement I : In the reaction below,

A single aldol product is formed in 100% yield.

Statement II : Cross aldol product is formed as major product.

Detailed Solution for Test: Aldol Condensation - Question 19

Both self-aldol of cyclohexanone (although minor one) and cross aldol are formed.

Test: Aldol Condensation - Question 20

Comprehension Type

Direction (Q. Nos. 20-22) This section contains a paragraph, describing theory, experiments, data, etc.
Three questions related to the paragraph have been given. Each question has only one correct answer among the four given options (a), (b), (c) and (d).

Passage

Aldol condensation is an important reaction in organic chemistry, particularly for the formation of carbon-carbon bonds. This reaction typically involves the enolate ion derived from an aldehyde or ketone reacting with another carbonyl compound to form a β-hydroxy aldehyde or β-hydroxy ketone. This product can undergo dehydration to form an α,β-unsaturated carbonyl compound. The reaction is usually catalyzed by a base, although acid-catalyzed versions are also known. The presence of at least one α-hydrogen in the reactant is crucial for the aldol condensation to occur. Acetaldehyde, for example, can undergo aldol condensation to yield 3-hydroxybutanal, which can then dehydrate to form crotonaldehyde.

Ques: In the aldol condensation reaction of acetaldehyde (CH₃CHO), the initial product formed before dehydration is:

Detailed Solution for Test: Aldol Condensation - Question 20

The initial product formed in the aldol condensation reaction of acetaldehyde (CH₃CHO) is 3-hydroxybutanal. Here’s how:

  • Acetaldehyde (CH₃CHO) has an α-hydrogen, which is necessary for forming the enolate ion.
  • The enolate ion then reacts with another acetaldehyde molecule.
  • This reaction forms 3-hydroxybutanal as the initial product
  • Crotonaldehyde is formed after the dehydration of 3-hydroxybutanal.

Correct Answer: c

Test: Aldol Condensation - Question 21

A is optically active and C is one of the several aldol possible in the above reaction.

Q. 

Besides C, the other six membered cyclic aldol formed in the above reaction is

Detailed Solution for Test: Aldol Condensation - Question 21

Test: Aldol Condensation - Question 22

A is optically active and C is one of the several aldol possible in the above reaction.

Q. 

The product B is stereomeric. If a mixture containing all stereoisomers of B is treated with excess of LiAIH4 followed by the acidification will give how many different isomeric diols ?

Detailed Solution for Test: Aldol Condensation - Question 22

*Answer can only contain numeric values
Test: Aldol Condensation - Question 23

One Integer Value Correct Type

Direction (Q. Nos. 23-27) This section contains 5 questions. When worked out will result in an integer from 0 to 9 (both inclusive).

Consider the following aldol condensation reaction,

Butanone + NaOH (Dil.) → Aldols

Q. 

How many different isomers (including stereoisomers) are formed above?


Detailed Solution for Test: Aldol Condensation - Question 23

*Answer can only contain numeric values
Test: Aldol Condensation - Question 24

Consider the following cross-aldol condensation reaction,


Q. 

How many different isomeric X are formed?


Detailed Solution for Test: Aldol Condensation - Question 24

*Answer can only contain numeric values
Test: Aldol Condensation - Question 25

Consider the following modified aldol condensation,

Q. 

How many ethanal, at the most, will react with one molecule of nitromethane?


Detailed Solution for Test: Aldol Condensation - Question 25

All three hydrogen can be deprotonated from nitromethane giving

*Answer can only contain numeric values
Test: Aldol Condensation - Question 26

Consider the following sequence of reaction, 

Q. 

How many different aldol isomers of X are formed?


Detailed Solution for Test: Aldol Condensation - Question 26

*Answer can only contain numeric values
Test: Aldol Condensation - Question 27

Consider the following sequence of reaction,


Q. 

If all undehydrated aldols (X) formed above by intramolecular aldol condensation are considered, how many pairs of enantiomers are formed?


Detailed Solution for Test: Aldol Condensation - Question 27

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