Aldehydes, Ketones and Carboxylic Acids Test

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Aldehydes, Ketones and Carboxylic Acids Test - 5

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Weekly Quiz Competition

Question 1
4 / -1

Arrange the following in the increasing order of reactivity with NH₃.

I. CH₂O
II. CH₃CHO
III. CH₃—CO—CH₃

A
I < II < III < IV

B
IV < III < II < I

C
III < IV < I < II

D
II < I < IV < III

Solution

This is because of steric hindrance because NH₃ attack carbonyl carbon as nucleophile (Sn₂) and then steric hindrance is the main factor.
Question 2
4 / -1

The major organic product formed in the following reaction is

A

B

C

D

Solution
Question 3
4 / -1

Which carbonyl compound below gives the reddish orange precipitate with 2, 4-dinitrophenyl hydrazine?

A

B

C

D

Solution

Conjugated aldehydes and ketones give reddish orange precipitate with 2,4-dinitrophenyl hydrazine. Non-conjugated aldehydes and ketones give orange precipitate in the same reaction.
Question 4
4 / -1

Which carbonyl compound below forms a single semicarbazone when allowed to react with semicarbazide?

A

B

C

D

Solution

It is symmetrical ketone, forms single semicarbazone with semicarbazide. All others are unsymmetrical, forms more than one stereoisomers of semicarbazones in the same reaction.
Question 5
4 / -1

A hydrocarbon X (C₇H₁₄) on ozonolysis followed by work-up with Zn- H₂O gives C₆H₁₂O as one of the product which on subsequent treatment with KOH/I₂ gives yellow precipitate and salt of a chiral acid. Hence, X could be

A

B

C

D

Solution

Ozonolysis of X gives C₆H₁₂O which has one carbon less than X. Hence, X must contain double bond at terminal carbon.
Question 6
4 / -1

Which gives more than one oximes on treatment with hydroxylamine?

A

B

C

D

Solution

It is unsymmetrical aldehyde, forms syn and anti oximes with hydroxylamine. All others are symmetrical, forms single oxime
Question 7
4 / -1

Which forms an unsaturated amine on treatment with cyclopentanone in slightly acidic medium?

A
CH₃NH₂

B
(CH₃)3N

C
NH₃

D

Solution

Secondary amine forms enamine with aldehydes or ketones.
Question 8
4 / -1

Consider the following reaction,
Q.
X (major) in the above reaction is

A

B

C

D

Solution
Question 9
4 / -1

What is the final major product Y in the following reaction?

A

B

C

D

Solution
Question 10
4 / -1

What is the final major product in the following reaction?

A

B

C

D

Solution
Question 11
4 / -1

Heating a mixture of sodium benzoate and soda lime gives

A
calcium benzoate

B
benzene

C
sodium benzoate

D
methane
Question 12
4 / -1

Formic acid and acetic acid are distinguished by reaction with

A
sodium ethoxide

B
sodium

C
HgCl₂

D
2,4-dinitrophenylhydrazine
Question 13
4 / -1

The reaction of ethyl formate with an excess of CH₃MgI followed by hydrolysis gives

A
ethanol

B
n-propyl alcohol

C
propanal

D
isopropyl alcohol
Question 14
4 / -1

An inorganic compound producing an organic compound on heating is

A
ammonium cyanate

B
soda lime

C
sodamide

D
potassium cyanide
Question 15
4 / -1

Comprehension Type
Direction (Q. Nos. 15-17) 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
Aidehydes and ketones react with ammonia and primary amines to form imines in slightly acidic condition. A typical reaction mechanism with a primary amine is as follows

The proper pH control is crucial to imine formation otherwise reaction does not proceed at appreciable rate.
However, if a secondary amine is reacted, no hydrogen is left on nitrogen on intermediate (I) for the deprotonation in step II. Hence, the reaction proceeds as

Enamine is a suitable intermediate route for α-alkyiation of a carbonyl compound.
Q.
What happens if imine form ation is carried out at very low pH?

A
Reaction occur at very fast rate

B
Amine gets protonated and becomes non-nucleophilic

C
Imine formed gets hydrolysed very easily

D
Imine formed gets protonated favouring backward reaction

Solution

At very low pH (highly acidic condition), amines get protonated and its nucleophilic character is lost.
Question 16
4 / -1

Aidehydes and ketones react with ammonia and primary amines to form imines in slightly acidic condition. A typical reaction mechanism with a primary amine is as follows

The proper pH control is crucial to imine formation otherwise reaction does not proceed at appreciable rate.
However, if a secondary amine is reacted, no hydrogen is left on nitrogen on intermediate (I) for the deprotonation in step II. Hence, the reaction proceeds as

Enamine is a suitable intermediate route for α-alkyiation of a carbonyl compound.
Q.
Which of the following is expected to give more than one imine when treated with CH₃NH₂?

A
CH₃CHO

B

C
H₂CO

D
(C₆H₅)₂CO

Solution
Question 17
4 / -1

Aidehydes and ketones react with ammonia and primary amines to form imines in slightly acidic condition. A typical reaction mechanism with a primary amine is as follows

The proper pH control is crucial to imine formation otherwise reaction does not proceed at appreciable rate.
However, if a secondary amine is reacted, no hydrogen is left on nitrogen on intermediate (I) for the deprotonation in step II. Hence, the reaction proceeds as

Enamine is a suitable intermediate route for α-alkyiation of a carbonyl compound.
Q.
What is the product X in the following reaction?

A

B

C

D

Solution
Question 18
4 / -1

One Integer Value Correct Type

Direction (Q. Nos. 18-21) This section contains 4 questions. When worked out will result in an integer from 0 to 9 (both inclusive).

Q.

In the following reaction, how many isomers of trioximes are formed?

A
6

B
7

C
8

D
9

Solution

Six isomers (stereoisomers) are possible for X.
Question 19
4 / -1

Consider the isomeric aldehydes with molar mass 100, if all the isomers (only structural) are treated independently with NH₂OH, how many of them would give more than two stereomeric oximes?

A
4

B
7

C
2

D
3

Solution

MW = 100 indicates that molecular formula of aldehyde is C₆H₁₂O . For obtain ing more than two oximes, aldehyde must exist stereomeric.

All the above has one chiral carbon each. Hence, when reacted with H₂NOH, forms more than two oximes.
Question 20
4 / -1

When formaldehyde reacts with ammonia, a typical compound called hexamethylene tetramine is formed. How many six membered rings are present in this compound?

A
4

B
5

C
9

D
11

Solution
Question 21
4 / -1

The smallest acyclic ketone that gives pair of diastereomers with CH₃NH₂ in slightly acidic medium has how many carbon atoms?

A
7

B
6

C
5

D
3

Solution

The ketone must contain a chiral carbon.