JEE Main > Organic Chemistry Some Basic Principles and Techniques

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Q 1.    

Correct4

Incorrect-1

Which of the following compounds easily undergoes homolytic bond fission?

A

{tex} \mathrm { CH } _ { 3 } - \mathrm { Cl } {/tex}

B

{tex} \mathrm { CH } _ { 3 } - \mathrm { CH } = \mathrm { O } {/tex}

{tex} \mathrm { H } - \mathrm { O } - \mathrm { H } {/tex}

D

{tex} \mathrm { NH } _ { 2 } - \mathrm { CH } _ { 3 } {/tex}

Explanation

Q 2.    

Correct4

Incorrect-1

Which of the following represents the mode of hybridisation {tex}\mathrm{sp^2 -sp^2 -sp-sp}{/tex} from left to right?

{tex} \mathrm { CH } _ { 2 } = \mathrm { CH } - \mathrm { C } \equiv \mathrm { N } {/tex}

B

{tex} \mathrm { HC } \equiv \mathrm { C } - \mathrm { C } \equiv \mathrm { CH } {/tex}

C

{tex} \mathrm { CH } _ { 2 } = \mathrm { C } = \mathrm { C } = \mathrm { CH } _ { 2 } {/tex}

D

{tex} \mathrm { CH } _ { 2 } = \mathrm { CH } - \mathrm { CH } = \mathrm { CH } _ { 2 } {/tex}

Explanation

Q 3.    

Correct4

Incorrect-1

Which of the following is an electron deficient molecule?

A

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 3 } {/tex}

{tex} \mathrm { BH } _ { 3 } {/tex}

C

{tex} \mathrm { SiH } _ { 4 } {/tex}

D

{tex} \mathrm { PH } _ { 3 } {/tex}

Explanation

Q 4.    

Correct4

Incorrect-1

One of the following pairs represents a set of nucleophile:

{tex} \mathrm { CN } ^ { - } {/tex} and {tex} \mathrm { NH } _ { 3 } {/tex}

B

{tex} \mathrm { AlCl } _ { 3 } {/tex} and {tex} \mathrm { Cl } ^ { - } {/tex}

C

{tex} \mathrm { H } ^ { + } {/tex} and {tex} \mathrm { H } _ { 2 } \mathrm { O } {/tex}

D

{tex} \mathrm { Br } ^ { + } {/tex} and {tex} \ddot { \mathrm { C } } \mathrm { Cl } _ { 2 } {/tex}

Explanation



Q 5.    

Correct4

Incorrect-1

The decreasing order of {tex} - 1 {/tex} effect of the following is:
{tex} \begin{array} { l l } { \text { I. } H _ { 3 } N ^ { \oplus } } & { \text { II. } \mathrm { NO } _ { 2 } } \\ { \text { III. } C N } & { \text { IV. } C O O H } \end{array} {/tex}

{tex} \mathrm { I } > \mathrm { II } > \mathrm { III } > \mathrm { IV } {/tex}

B

{tex} \mathrm { II } > \mathrm { I } > \mathrm { III } > \mathrm { IV } {/tex}

C

{tex} \mathrm { I } > \mathrm { II } > \mathrm { III } > \mathrm { IV } {/tex}

D

{tex} \mathrm { II } > \mathrm { I } > \mathrm { IV } > \mathrm { III } {/tex}

Explanation

Q 6.    

Correct4

Incorrect-1

Which of the following has highest {tex} K _ { a } {/tex} value?

A

B

C

Explanation



Q 7.    

Correct4

Incorrect-1

Which of following has lowest {tex} \mathrm { pK } _ { \mathrm { a } } {/tex} value?

A

{tex} \mathrm { Cl } - \mathrm { CH } _ { 2 } - \mathrm { CO } _ { 2 } \mathrm { H } {/tex}

B

{tex} \mathrm { Cl } - \mathrm {\underset{\mid} CH } - \mathrm { CO } _ { 2 } \mathrm { H } {/tex}
{tex}\qquad\mathrm { Cl } {/tex}

{tex} \mathrm { Cl } _ { 3 } \mathrm { C } - \mathrm { CO } _ { 2 } \mathrm { H } {/tex}

D

{tex} \mathrm { CH } _ { 3 } - \mathrm { CO } _ { 2 } \mathrm { H } {/tex}

Explanation





Q 8.    

Correct4

Incorrect-1

Arrange the following compound in order of decreasing acidity
{tex} \mathrm { CH } _ { 3 } - \mathrm { CH } _ { 2 } - \mathrm { OH } ( \alpha ) ; \mathrm { CH } _ { 3 } - \mathrm { CH } _ { 3 } - \mathrm {\stackrel { \oplus } OH } _ { 2 } ( \beta ) ; \mathrm { CH } _ { 3 } - \mathrm { O } - \mathrm { CH } _ { 3 } ( \gamma ) {/tex}

A

{tex} \alpha > \beta > \gamma {/tex}

{tex} \beta > \alpha > \gamma {/tex}

C

{tex} \gamma > \beta > \alpha {/tex}

D

{tex} \alpha > \gamma > \beta {/tex}

Explanation

Q 9.    

Correct4

Incorrect-1

Amongst the amines {tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { NH } _ { 2 } {/tex} (I), {tex} \mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 } {/tex} (II)
{tex} \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { NH } \,\,(\mathrm { III } ) {/tex} and {tex} \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { N } \,\,( \mathrm { IV } ) {/tex} the order of basic- ity (in aqueous medium) is-

{tex} \mathrm { I } < \mathrm { IV } < \mathrm { II } < \mathrm { III } {/tex}

B

{tex} \mathrm { IV } < \mathrm { III } < \mathrm { II } < \mathrm { I } {/tex}

C

{tex} \mathrm { I } < \mathrm { II } < \mathrm { III } < \mathrm { IV } {/tex}

D

{tex} \mathrm { II } < \mathrm { III } < \mathrm { IV } < \mathrm { I } {/tex}

Explanation





Q 10.    

Correct4

Incorrect-1

The order of decreasing stability of the anions
{tex} \begin{array} { c c c c } { \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } ^ { - } } & { \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } ^ { - } } & { \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } ^ { - } } & { \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { CH } _ { 2 } ^ { - } \text {is- } } \\ { \mathrm { I } } & { \mathrm { II } } & { \mathrm { III } } & { \mathrm { IV } } \end{array} {/tex}

A

{tex} \mathrm { I } > \mathrm { II } > \mathrm { III } > \mathrm { IV } {/tex}

{tex} \mathrm { IV } > \mathrm { III } > \mathrm { II } > \mathrm { I } {/tex}

C

{tex} \mathrm { IV } > \mathrm { I } > \mathrm { II } > \mathrm { III } {/tex}

D

{tex} \mathrm { I } > \mathrm { II } > \mathrm { IV } > \mathrm { III } {/tex}

Explanation



Q 11.    

Correct4

Incorrect-1

In the formate ion , the two carbon-ox- ygen bonds are found to be equal. This is because

A

the formate ion {tex} \mathrm { HCOO } ^ { - } {/tex} is obtained by the removal of a proton from {tex} \mathrm { HCOOH } {/tex}

B

the carbon atom in {tex} \mathrm { HCOO } ^ { - } {/tex} is {tex} \mathrm { sp } ^ { 2 } {/tex} hybridised

C

the formate ion is a tautomeric mixture of

the formate ion is a resonance hybrid of {tex} f {/tex} the two equivalent resonance structures

Explanation

Q 12.    

Correct4

Incorrect-1

The hybridisation states of the nitrogen atoms at in pyridine, piperidine and pyrrole are respectively:

{tex} \mathrm { sp } ^ { 2 } , \mathrm { sp } ^ { 3 } {/tex} and {tex} \mathrm { sp } ^ { 2 } {/tex}

B

{tex} \mathrm { sp } ^ { 2 } , \mathrm { sp } ^ { 3 } {/tex} and {tex} \mathrm { sp } ^ { 3 } {/tex}

C

{tex} \mathrm { sp } ^ { 3 } , \mathrm { sp } ^ { 3 } {/tex} and {tex} \mathrm { sp } ^ { 3 } {/tex}

D

{tex} s p ^ { 2 } , s p ^ { 2 } {/tex} and {tex} s p ^ { 2 } {/tex}

Explanation

Q 13.    

Correct4

Incorrect-1


The least stable canonical structure among these is:
{tex} \begin{array} { l l } { \text { (1) } \mathrm { I } } & { \text { (2) II } } \\ { \text { (3) III } } & { \text { (4) all are equally stable } } \end{array} {/tex}

A

{tex} \mathbf { I } {/tex}

{tex} \mathbf { II } {/tex}

C

{tex} \mathrm { III } {/tex}

D

all are equally stable

Explanation

Q 14.    

Correct4

Incorrect-1

Which one of the following is most stable?

A

B

D

Explanation





Q 15.    

Correct4

Incorrect-1

Pyridine is less basic than triethyl amine because:

A

Pyridine has aromatic character

B

Nitrogen in pyridine is {tex} s p ^ { 2 } {/tex} hybridised

C

Pyridine is a cyclic system

Lone pair of nitrogen is delocalised in pyridine

Explanation



Q 16.    

Correct4

Incorrect-1

Which is an aromatic compound?

A

C

D

Explanation



Q 17.    

Correct4

Incorrect-1

Which of the following is the strongest nucleophile?

B

C

D

{tex} I ^ { \Theta } {/tex}

Explanation





Q 18.    

Correct4

Incorrect-1

Which of the following is the correct order for bond energy for {tex} \mathrm { C } - \mathrm { H } {/tex} bonds in these compounds?

A

{tex} \mathrm { Y } > \mathrm { Z } > \mathrm { X } {/tex}

B

{tex} \mathrm { X } > \mathrm { Z } > \mathrm { Y } {/tex}

{tex} \mathrm { X } > \mathrm { Y } > \mathrm { Z } {/tex}

D

{tex} Z > X > Y {/tex}

Explanation





Q 19.    

Correct4

Incorrect-1

The correct order of decreasing acidity of the compounds is:

{tex} \mathrm { III } > \mathrm { IV } > \mathrm { II } > \mathrm { I } {/tex}

B

{tex} \mathrm { IV } > \mathrm { III } > \mathrm { I } > \mathrm { II } {/tex}

C

{tex} \mathrm { III } > \mathrm { II } > \mathrm { I } > \mathrm { IV } {/tex}

D

{tex} \mathrm { II } > \mathrm { III } > \mathrm { IV } > \mathrm { I } {/tex}

Explanation



Q 20.    

Correct4

Incorrect-1

Compare heat of hydrogenation of the following:

A

i > ii > iii

iii > ii > i

C

ii > i > iii

D

ii > iii > i

Explanation

Q 21.    

Correct4

Incorrect-1

Compare rate of EAS

A

{tex} a > b > c > d {/tex}

{tex} a > c > b > d {/tex}

C

{tex} c > a > b > d {/tex}

D

{tex} c > b > a > d {/tex}

Explanation

Q 22.    

Correct4

Incorrect-1

Identify the correct order of the ease of dehydration of the following compounds.

A

{tex} \mathrm { I } > \mathrm { II } > \mathrm { III } {/tex}

{tex} \mathrm { III } > \mathrm { II } > \mathrm { I } {/tex}

C

{tex} \mathrm { I } > \mathrm { III } > \mathrm { II } {/tex}

D

III {tex} > I > I {/tex}

Explanation





Q 23.    

Correct4

Incorrect-1

Which of the following compounds has the highest {tex} \mathrm { pK } _ { \mathrm { a } } {/tex} value?

B

C

D

Explanation





Q 24.    

Correct4

Incorrect-1

Least stable carbocation amongst following is:

A

B

D

Explanation

Q 25.    

Correct4

Incorrect-1

Consider the following compounds:

A

{tex} \mathrm { I } > \mathrm { II } > \mathrm { III } > \mathrm { IV } {/tex}

B

{tex} \mathrm { II } > \mathrm { III } > \mathrm { I } > \mathrm { IV } {/tex}

{tex} \mathrm { IV } > \mathrm { I } > \mathrm { III } > \mathrm { II } {/tex}

D

{tex} \mathrm { IV } > \mathrm { I } > \mathrm { II } > \mathrm { III } {/tex}

Explanation