Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions


29 Questions MCQ Test Chemistry Class 12 | Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions


Description
This mock test of Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions for Class 12 helps you for every Class 12 entrance exam. This contains 29 Multiple Choice Questions for Class 12 Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions exercise for a better result in the exam. You can find other Test: Aldehydes, Ketones And Carboxylic Acids 1 - From Past 28 Years Questions extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

In a set of reactions acetic acid yielded a product D.

The structure of D would be:                   [2005]

Solution:

QUESTION: 2

A carbonyl compound reacts with hydrogencyanide to form cyanohydrin which on hydrolysisforms a racemic mixture of  α-hydroxy acid. Thecarbonyl compound is       [2006]

Solution:

Out of given compound only acetaldehyde
can form optical active hydroxy acid as it
contains one asymmetric carbon atom as
marked below :

QUESTION: 3

Nucleophilic addition reaction will be mostfavoured in [2006]

Solution:

Aldehydes are more reactive than ketones
due to +I effect of –CH3 group. There are
two – CH3 group in acetone which reduces
+ve charge density on carbon atom of
carbonyl group. More hindered carbonyl
group too becomes less reactive. So in the
give case CH3CHO is the right choice.

QUESTION: 4

Self condensation of two moles of ethyl acetatein presence of sodium ethoxide yields [2006]

Solution:

It is an example of Claisen condensation. The
product is acetoacetic ester.

QUESTION: 5

In a set of reactions propionic acid yielded a compound D.                  [2006]

The structure of D would be

Solution:

For reaction,
Hence, compound 'D' is CH3-CH2-NH2

QUESTION: 6

Reduction of aldehydes and ketones intohydrocarbons using zinc amalgam and conc. HClis called [2007]

Solution:

QUESTION: 7

Which of the following represents the correctorder of the acidity in the given compounds?          [2007]

Solution:

Electron withdrawing substituent (like
halogen, —NO2, C6H5 etc.) would disperse
the negative charge and hence stabilise the
carboxylate ion and thus increase acidity
of the parent acid. On the other hand,
electron-releasing substituents would
intensify the negative charge, destabilise
the carboxylate ion and thus decrease
acidity of the parent acid.
Electronegativity decreases in order
F > Cl > Br
and hence –I effect also decreases in the
same order, therefore the correct option is

FCH2COOH > ClCH2COOH > BrCH2COOH> CH3COOH

QUESTION: 8

Which one of the following on treatment with50% aqueous sodium hydroxide yields thecorresponding alcohol and acid? [2007]

Solution:

Aldehydes containing no α-hydrogen
atom on warming with 50% NaOH or KOH
undergo disproportionation i.e. self
oxidation - reduction known as cannizzaro’s
reaction.

QUESTION: 9

The product formed in Aldol condensation is       [2007]

Solution:

Aldehydes and ketones having at least one
α-hydrogen atom in presence of dilute
alkali give β-hydroxy aldehyde or β-
hydroxy ketone

QUESTION: 10

Acetophenone when reacted with a base, C2H5ONa, yields a stable compound which has the structure. [2008]

Solution:

Thus two molecules of acetophenone
condense to form a β-hydroxy ketone which
gets dehydrated in the presence of acid
upon heating to form α β -unsaturated
compound.
i.e., option (a) is correct.
[Note: It is aldol condensation].

QUESTION: 11

The relative reactivities of acyl compounds towardsnucleophilic substitution are in the order of : [2008]

Solution:

The relative reactivities of acyl compounds
towards nucleophilic substitution follow
the order Acyl halides > Acid anhydride >
Ester > Amide. Thus the correct answer is
(a).

QUESTION: 12

Propionic acid with Br2|P yields a dibromo product. Its structure would be: [2009]

Solution:

This reaction is an example of Hell - Volhard
Zelinsky reaction. In this reaction acids
containing α– H on treatment with X2 /P
give di-halo substituted acid.

QUESTION: 13

In a set of reactions, ethylbenzene yielded a product D.        [2010]

Solution:

QUESTION: 14

Which of the following reactions will not resultin the formation of carbon-carbon bonds?

Solution:

Note that new C–C bond is formed is a, c and d.

QUESTION: 15

Following compounds are given:

(a) CH3CH2OH

(b)  CH3COCH3

(c) 

(d)  CH3OH

Which of the above compound(s), on being warmed with iodine solution and NaOH, will  give iodoform? [2010]

Solution:

Among the given compounds only
CH3OH does not give iodoform reaction.

QUESTION: 16

Which one of the following compounds will be most readily dehydrated?       [2010]

Solution:

The intermediate is carbocation which is
destabilised by C = O group (present on ��-
carbon to the –OH group) in the first three
cases. In (d), α–hydrogen is more acidic which
can be removed as water. Moreover, the
positive charge on the intermediate carbocation
is relatively away from the C = O group.

∴ Correct choice : (d)

QUESTION: 17

Clemmensen reduction of a ketone is carried outin the presence of which of the following ? [2011]

Solution:

Clemmensen reduction is

QUESTION: 18

The order of reactivity of phenyl magnesium bromide (PhMgBr) with the following compounds           [2011 M]

Solution:

The reactivity of the carbonyl group toward
the nucleophilic addition reactions depend
upon the magnitude of the positive charge
on the carbonyl carbon atom (electronic
factor) and also on the crowding around
the carboxyl carbon atom in the transition
state (steric factor). Both these factors
predict the following order

(due to steric crowding).

QUESTION: 19

Match the compounds given in List-I with List-II and select the suitable option using the code given below : [2011 M]

Solution:

(a) 

 

 

(b) 

(d) 

QUESTION: 20

An organic compound ‘A’ on treatment with NH3 gives ‘B’ which on heating gives ‘C’, ‘C’ whentreated with Br2 in the presence of KOH produces ethylamine. Compound ‘A’ is:[2011 M]

Solution:

Since, C when heated with Br2 in presence
of KOH produces ethylamine, hence it must
be propanamide and hence the organic
compound (A) will be propanoic acid. The
reactions follows.

QUESTION: 21

Predict the product in the given reaction.            [2012]

Solution:

Cannizzaro reaction - when an aldehyde
containing no α – H undergo reaction in
presence of 50% KOH. It disproportionates
to form a molecule of carboxylic acid and a
molecule of alcohol.

QUESTION: 22

Acetone is treated with excess of ethanol in the presence of hydrochloric acid. The product obtained is : [2012]

Solution:

Anhydrous alcohols add to the carbonyl
group of aldehydes in the presence of
anhydrous hydrogen chloride to form
acetals via hemiacetals.

QUESTION: 23

The correct order of decreasing acid strength oftrichloroacetic acid (A), trifluoroacetic acid (A),acetic acid (C) and formic acid (D) is : [2012]

Solution:

CF3 COOH > CCl3 COOH > HCOOH >
CH3COOH (Ka order)
The halogenated fatty acids are much
stronger acids than the parent fatty acid
and more over the acidity among the
halogenated fatty acid is increased almost
proportionately with the increase in
electronegativity of the halogen present.
Further formic acid having no alky group is
more acidic than acetic acid.

QUESTION: 24

CH3CHO and C6H5CH2CHO can be distinguishedchemically by : [2012]

Solution:

CH3CHO gives Iodoform test but
C6H5CH2CHO does not give Iodoform test
due to absence of methyl group

QUESTION: 25

Consider the following reaction :

The product ‘A’ is : [2012 M]

Solution:

QUESTION: 26

Consider the reaction :
RCHO + NH2NH2 → RCH = N – NH2

What sort of reaction is it ? [2012 M]

Solution:

Such reactions take place in slightly acidic
medium and involve nucleophilic addition
of the ammonia derivative.

*Multiple options can be correct
QUESTION: 27

Which of the following compounds will give ayellow precipitate with iodine and alkali ?[2012 M]

Solution:

It is iodoform reaction. Acetophenone 

 and 2-Hydroxypropane 

both give a yellow
precipitate of CHI3 (iodoform) with iodine
and alkali.

QUESTION: 28

The order of stability of the following tautomeric compounds is :

Solution:

Enolic form predominates in compounds
containing two carbonyl groups separated
by a – CH2 group. This is due to
following two factors.
(i) Presence of conjugation which
increases stability.
(ii) Formation of intramolecular hydrogen
bond between enolic hydroxyl
group and second carbonyl group
which leads to stablisation of the
molecule. Hence the correct answer is
III > II > I.

QUESTION: 29

Reaction by which Benzaldehyde cannot be prepared : [NEET 2013]

Solution:

Zn/Hg and HCl reduce carboxyl group to
methylene group (Clemmensen reduction).