Test: Previous Year Questions: Carbonyl Group


18 Questions MCQ Test Chemistry Class 12 | Test: Previous Year Questions: Carbonyl Group


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This mock test of Test: Previous Year Questions: Carbonyl Group for JEE helps you for every JEE entrance exam. This contains 18 Multiple Choice Questions for JEE Test: Previous Year Questions: Carbonyl Group (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Previous Year Questions: Carbonyl Group quiz give you a good mix of easy questions and tough questions. JEE students definitely take this Test: Previous Year Questions: Carbonyl Group exercise for a better result in the exam. You can find other Test: Previous Year Questions: Carbonyl Group extra questions, long questions & short questions for JEE on EduRev as well by searching above.
QUESTION: 1

Q.1 End product of the following reaction is –                          [AIEEE-2002]

Solution:
QUESTION: 2

Picric acid is –                                   [AIEEE-2002]

Solution:
QUESTION: 3

In the anion HCOOthe two carbon-oxygen bonds are found to be of equal length. What is the reason for it ?        [AIEEE-2003]

Solution:

Through resonance both resonating structures are equivalent. That is why two C−0 bond lengths are found to be equal.

QUESTION: 4

When CH2 = CHCOOH is reduced with LiAlH4, the compound obtained is:      [AIEEE-2003]

Solution:

The correct answer is option C
LiAlH4  can reduce the carboxylic acid group without affecting the double bond because alkene is an electron-rich species.

QUESTION: 5

The general formula CnH2nO2 could be for open chain :         [AIEEE-2003]

Solution:

The correct answer is option D
The general formula Cn​H2n​O2​ could be for open chain carboxylic acids. Thus, butanoic acid CH3​−CH2​−CH2​−COOH has formula C4​H8​O2​. And, decanoic acid CH3​−(CH​2)8​−COOH has formula C10​H20​O2.​.

QUESTION: 6

Which one of the following does not have sp2 hybridized carbon ?      [AIEEE-2004]

Solution:

Option C is the correct answer.
So, acetonitrile does not have sp2 hybridized carbon.

QUESTION: 7

Consider the acidity of the carboxylic acids :      [AIEEE-2004]

(a) PhCOOH

(b) o – NO2C6H4COOH

(c) p – NO2C6H4COOH

(d) m – NO2C6H4COO

Which of the following order is correct ?

Solution:

The correct answer is option D

NO2 group at any position shows electron withdrawing effect, thus acid strength is increased. But o -nitro benzoate ion is stabilised by intramolecular H-bonding like forces, hence its acid strength is maximum. Thus, the order of acid strength is (ii) > (iii) > (iv) > (i)
The effect is more pronounced at para position than meta.

QUESTION: 8

Rate of the reaction :

is fastest when Z is :              [AIEEE-2004]

Solution:

The correct answer is Option D.
Cl is the best leaving group being the weakest nucleophile out of NH2− , Cl− , OC2H5 and CH3COO
So, when Z is Cl , the ion leaves faster thus making the reaction the fastest when Z is Cl .

QUESTION: 9

Consider the acidity of the carboxylic acids :
(1) PhCOOH

(2) 0-NO2C6H4COOH

(3) p-NO2C6H4COOH

(4) m-NO2C6H4COOH
Which of the following order is correct ?     [AIEEE-2004]

Solution:

The correct answer is option A
2>3>4>1
Electron withdrawing groups increase the acidity of benzoic acid, o−o-isomer will have higher acidity than mm and pp isomer due to ortho effect. The NO2NO2 group at pp position has a more pronounced electron withdrawing effect than −NO2-NO2 group at mm position. Hence order of acidity is

 

QUESTION: 10

On mixing ethyl acetate with aqueous sodium chloride, the composition of the resultant solution is :
[AIEEE-2004]

Solution:

aqueous NaCl is a neutral compound. Thus no reaction takes place between ethyl acetate and aqueous NaCl.

Thus resultant solution will be CH3COOC2​H5​ + NaCl 

QUESTION: 11

Which one of the following is reduced with zinc and hydrochloric acid to give the corresponding
hydrocarbon :        [AIEEE-2004]

Solution:

The correct answer is option A
Butan - 2 - one will get reduced into butane when treated with zinc and hydrochloric acid following Clemmensen reaction whereas Zn/HCl do not reduce ester, acid and amide

QUESTION: 12

The compound formed as a result of oxidation of ethyl benzene by KMnO4 is –        [AIEEE-2007]

Solution:

The correct answer is option C
The compound formed as a result of oxidation of ethyl benzene by alkaline KMnO4​ is benzoic acid. 
Other reagents that can be used are acidified potassium dichromate or dilute nitric acid.

QUESTION: 13

A liquid was mixed with ethanol and a drop of concentrated H2SO4 was added. A compound with a fruity
smell was formed. The liquid was :         [AIEEE-2009]

Solution:

The correct answer is Option D.

The fruity smell is evolved due to the formation of ester when ethanol and acid are treated in the presence of concentrated H2SO4.
The reaction is 
CH3COOH + CH3CH2OH → CH3COOC2H5

QUESTION: 14

Reaction
Primary amine + CHCl3 + KOH → product, here product will be -         [AIEEE-2002]

Solution:

The correct answer is Option B.
When primary amine reacts with CHCl3 in alcoholic KOH, the product is isocyanide which is foul smelling.
R−NH2+CHCl3+3KOH -ΔR−NC+3KCl+3H2O
This reaction is known as carbylamine test / Isocyande test. This test is not given by secondary or tertiary amines.

QUESTION: 15

The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is -           [AIEEE-2004]

Solution:

The correct answer is option A
It is ferri ferrocyanide
6NaCN+FeSO4→Na4[Fe(CN)6]+Na2SO4
3Na4[Fe(CN)6]+2Fe2(SO4)3→Fe4[Fe(CN)6]3+6Na2SO4
Prussian blue
 

QUESTION: 16

Which one of the following methods is neither meant for the synthesis nor for separation of amines ?
[AIEEE-2005]

Solution:

The correct answer is Option D.

Wurtz reaction is used to produce alkanes from alkyl halides.
2RX+2Na (in ether)→R−R+2NaX
Example :
2CH3Cl+2Na (in ether)→C2H6+2NaCl
So, the Wurtz reaction has nothing to do with amines.

QUESTION: 17

Reaction of cyclohexanone with dimethylamine in the presence of catalytic amount of an acid forms a
compound if water during the reaction is continuously removed. The compound formed is generally known
as –       [AIEEE-2005]

Solution:

The correct answer is option A
The reaction of cyclohexanone with dimethylamine, in the presence of a catalytic amount of an acid forms a compound as shown in the reaction sequence. During the reaction, if water is continuously removed, the compound formed is generally known as an enamine.

QUESTION: 18

In the chemical reaction, CH3CH2NH2 + CHCl3 + 3KOH → (A) + (B) + 3H2O, the compounds (A) and (B)
are respectively -     [AIEEE-2007]

Solution:

The correct answer is option D
In the chemical reaction,
CH3​CH2​NH2​+CHCl3​+3KOH→(A)+(B)+3H2​O
The compounds(A) and (B) are C2​H5​NC and 3KCl respectively. The given reaction is carbylamine test/Isocyanide test in which aliphatic or aromatic primary amines on heating with chloroform and alcoholic potassium hydroxide give foul smelling alkyl isocyanides or carbylamines. Secondary or tertiary amines do not give this test.

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