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Explore popular questions from Organic Chemistry Some Basic Principles and Techniques for JEE Main. This collection covers Organic Chemistry Some Basic Principles and Techniques previous year JEE Main questions hand picked by experienced teachers.

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Organic Chemistry Some Basic Principles and Techniques

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Q 1. {tex} \left( \mathrm { NH } _ { 4 } \right) _ { 2 } \mathrm { Cr } _ { 2 } \mathrm { O } _ { 7 } {/tex} on heating gives a gas which is also given by

Heating {tex} \mathrm { NH } _ { 4 } \mathrm { NO } _ { 2 } {/tex}

B

Heating {tex} \mathrm { NH } _ { 4 } \mathrm { NO } _ { 3 } {/tex}

C

{tex} \mathrm { Mg } _ { 3 } \mathrm { N } _ { 2 } + \mathrm { H } _ { 2 } \mathrm { O } {/tex}

D

{tex} \mathrm { Na } ( \mathrm { com } . ) + \mathrm { H } _ { 2 } \mathrm { O } _ { 2 } {/tex}

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Q 2. 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

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Q 3. Amongst the amines {tex} \mathrm { C } _ { 6 } \mathrm { H } _ { 5 } \mathrm { NH } _ { 2 } {/tex} {tex}(\mathrm { I } ) {/tex}, {tex} \mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 } {/tex} {tex}(\mathrm { II } ) {/tex} {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 basicity (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



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Q 4. 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


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Q 5. 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

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Q 6. Which one of the following is most stable?

A

B

D

Explanation



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Q 7. What is the decreasing order of stability of the ions?

A

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

B

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

C

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

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

Explanation


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Q 8. 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

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Q 9. 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





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Q 10.

A

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

B

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

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

D

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

Explanation



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Q 11. Following carbocation rearranges to from:

B

C

D

Explanation

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Q 12. Among the following which is more reactive toward {tex} \mathrm { AgNO } _ { 3 } ? {/tex}

A

C

D

Explanation

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Q 13. The correct order of basic strength of the following is:

A

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

B

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

C

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

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

Explanation



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Q 14. Which of the following compounds has the highest {tex} \mathrm { pK } _ { \mathrm { a } } {/tex} value?

B

C

D

Explanation





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Q 15. Arrange {tex} 2,4,6 {/tex} -trinitrophenol {tex} ( 1 ; 2,4 \text { -dinitrophenol } {/tex} (II); {tex} o {/tex} -nitrophenol (III) and {tex} p {/tex} -nitrophenol (IV) in order of acidity:

A

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

B

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

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

D

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

Explanation





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Q 16. {tex} \alpha , \beta {/tex} and {tex} \gamma {/tex} are three {tex} ( \mathrm { C } - \mathrm { O } ) {/tex} bonds in methyl acetate;

the bond lengths are in the order:

A

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

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

C

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

D

{tex} \alpha < \beta = \gamma {/tex}

Explanation

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Q 17. Which of the following cations is the most stable?

A

B

D

Explanation



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Q 18. Electrophile {tex} \mathrm {\overset{ \oplus } NO } _ { 2 } {/tex} attacks the following:

In which cases {tex} \mathrm {\overset{ \oplus } NO } _ { 2 } {/tex} will attack at meta position

A

II and IV

II and III

C

II and IV

D

I only

Explanation

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Q 19.
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

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Q 20. 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





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Q 21. 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

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Q 22.
Product (A) is :

B

C

D

Explanation



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Q 23. Which of the following will have the lowest pK{tex} _ { a } {/tex} value?

B

C

D

Explanation







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Q 24. The correct order of increasing basic nature for the following compounds is:

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

B

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

C

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

D

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

Explanation

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Q 25. What is the hybridisation of {tex} \mathrm { C } _ { 1 } , \mathrm { C } _ { 2 } , \mathrm { C } _ { 3 } {/tex} carbon in the following compound?

A

{tex} s p ^ { 3 } , s p ^ { 3 } , s p ^ { 3 } {/tex}

B

{tex} s p ^ { 3 } , s p ^ { 2 } , s p ^ { 2 } {/tex}

C

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

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

Explanation