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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. Aniline has high boiling point, high vapour pressure at {tex} 100 ^ { \circ } \mathrm { C } {/tex} and is insoluble in water. Aniline is therefore, separated by:

Steam distillation

B

Simple distillation

C

Distillation at low pressure

D

Sublimation

Explanation

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Q 2. {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 3. 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

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Q 4. 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 5. 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 6. 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 7. 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 8. Which one of the following is most stable?

A

B

D

Explanation



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Q 9. 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 10. 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 11. 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 12. Stability order of the following resonating structure will be-

{tex} \mathrm { i } > \mathrm { ii } > \mathrm { iii } > \mathrm { iv } {/tex}

B

ii {tex} > \mathrm { i } > {/tex} iii {tex} > {/tex} iv

C

iii {tex} > {/tex} ii {tex} >{/tex} i > iv

D

{tex} \mathrm { i } > {/tex} iii {tex} > {/tex} ii {tex} > {/tex} iv

Explanation

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Q 13.

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 14. The electrophile, {tex} \mathrm { E } ^ { \oplus } {/tex} attacks the benzene ring to
generate the intermediate {tex} \sigma {/tex} -complex. Of the following, which {tex} \sigma {/tex} -complex is of lowest energy?

A

B

D

Explanation



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Q 15. Which of the following compounds has wrong IUPAC name?

A

B

D

Explanation

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Q 16. The {tex} \mathrm {IUPAC}{/tex} name of the compound shown below is

A

{tex} 2 -bromo- {tex} - 6 {/tex} -chlorocyclohex-{tex} l -ene{/tex}

B

{tex} 6 - bromo- 2 {/tex} -chlorocyclohexene

{tex} 3 -bromo- 1{/tex} -chlorocyclohexene

D

{tex}1 -bromo- {tex} - 3 {/tex} -chlorocyclohexene.

Explanation



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Q 17. The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is

{tex} \mathrm { Fe } _ { 4 } \left[ \mathrm { Fe } ( \mathrm { CN } ) _ { 6 } \right] _ { 3 } {/tex}

B

{tex} \mathrm { Na } _ { 3 } \left[ \mathrm { Fe } ( \mathrm { CN } ) _ { 6 } \right] {/tex}

C

{tex} \mathrm { Fe } ( \mathrm { CN } ) _ { 3 } {/tex}

D

{tex} \mathrm { Na } _ { 4 } \left[ \mathrm { Fe } ( \mathrm { CN } ) _ { 5 } \mathrm { NOS } \right. {/tex}

Explanation


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Q 18. Arrangement of {tex} \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } - , \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } - \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - {/tex} when attached to benzyl or an unsaturated group in increasing order of inductive effect is

A

{tex} \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } - < \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } - < \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - {/tex}

{tex} \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - < \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } - < \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } - {/tex}

C

{tex} \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } - < \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } - < \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - {/tex}

D

{tex} \left( \mathrm { CH } _ { 3 } \right) _ { 3 } \mathrm { C } - < \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } - < \left( \mathrm { CH } _ { 3 } \right) _ { 2 } \mathrm { CH } - {/tex}

Explanation



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Q 19. Racemic mixture is formed by mixing two

A

isomeric compounds

B

chiral compounds

C

meso compounds

optical isomers.

Explanation



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Q 20. Which of the following is not an electrophile

A

{tex} C l ^ { + } {/tex}

{tex} N a ^ { + } {/tex}

C

{tex} H ^ { + } {/tex}

D

{tex} B F _ { 3 } {/tex}

Explanation

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Q 21. The shape of carbonium is

Planar

B

Pyramidal

C

Linear

D

None of these

Explanation

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Q 22. How many primary amines are possible for the formula {tex} C _ { 4 } H _ { 11 } N {/tex}

A

{tex} 1 {/tex}

B

{tex} 2 {/tex}

C

{tex} 3 {/tex}

{tex} 4 {/tex}

Explanation

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Q 23. The IUPAC name of the compound

A

3-diisopropyl-2,4-dimethylpentane

B

2,4-dimethyl-3-diisopropylbutane

2,4-dimethyl-3-3-bis(1-methylethyl) pentane

D

None of these

Explanation

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Q 24. The IUPAC name of the compound

A

3-methyl-6-ethylcyclohexene

B

6-ethyl-3-methyl cyclohexene

3-ethyl-6-methyl cyclohexene

D

6-methyl-3-ethyl cyclohexene

Explanation

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Q 25. Which of the following reactions will not generate a carbanion?

A

B

D

Explanation