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CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323214 An organic compound $C_{3} H_{6} O$ does not give a precipitate with 2, 4-dinitrophenyl hydrazine reagent and does not react with sodium metal. It could be

1

{CH}_{3} - {CH}_{2} - CHO

2

{CH}_{3} - CO - {CH}_{3}

3

{CH}_{2} = CH - {CH}_{2} OH

4

{CH}_{2} = CH - {OCH}_{3}

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323215 In the presence of light, perchlorodiethyl ether is obtained from diethyl ether.
${(C_{2} H_{5})}_{2} O \overset{{Cl}_{2}}{⟶} {(C_{2} {Cl}_{5})}_{2} O$
The mechanism through which this reaction proceed is

1 Addition mechanism

2 Nucleophilic substitution mechanism

3 Free radical substitution mechanism

4 Elimination mechanism

Explanation:

The given reaction is,
${(C_{2} H_{5})}_{2} O \overset{C l_{2}}{\to} {(C_{2} C l_{5})}_{2} O$
The reaction proceeds by a free - radical mechanism and $α$ - substitution occurs readily because of resonance stabilisation of the intermediate.
$C l_{2} \overset{h υ}{\to} C l^{∙} + C l^{∙}$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - C H_{2} R' \overset{C l^{∙}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' + HCl$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \leftrightarrow R \overset{∙}{\underset{∙ ∙}{O}} = CHR'$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \overset{C l_{2}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - CHClR' + C l^{∙}$

AIIMS - 2017

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323216 The presene of peroxides in old samples of ethers is detetced by shaking them with a freshly prepared solution of ${FeSO}_{4}$ followed by the addition of KCNS. The appearance of which colour indicates the presence of peroxides?

1 Blue

2 Green

3 Red

4 Brown

Explanation:

Due to the formation of $Fe (SCN)_{3}$ . Which is blood red colour substance.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323217 Which of the following cannot form Oxonium salts with diethyl ether?

1

HCl

2

HBr

3

H_{2} {SO}_{4}

4

HCN

Explanation:

$HCN$ is a weak acid.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323214 An organic compound $C_{3} H_{6} O$ does not give a precipitate with 2, 4-dinitrophenyl hydrazine reagent and does not react with sodium metal. It could be

1

{CH}_{3} - {CH}_{2} - CHO

2

{CH}_{3} - CO - {CH}_{3}

3

{CH}_{2} = CH - {CH}_{2} OH

4

{CH}_{2} = CH - {OCH}_{3}

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323215 In the presence of light, perchlorodiethyl ether is obtained from diethyl ether.
${(C_{2} H_{5})}_{2} O \overset{{Cl}_{2}}{⟶} {(C_{2} {Cl}_{5})}_{2} O$
The mechanism through which this reaction proceed is

1 Addition mechanism

2 Nucleophilic substitution mechanism

3 Free radical substitution mechanism

4 Elimination mechanism

Explanation:

The given reaction is,
${(C_{2} H_{5})}_{2} O \overset{C l_{2}}{\to} {(C_{2} C l_{5})}_{2} O$
The reaction proceeds by a free - radical mechanism and $α$ - substitution occurs readily because of resonance stabilisation of the intermediate.
$C l_{2} \overset{h υ}{\to} C l^{∙} + C l^{∙}$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - C H_{2} R' \overset{C l^{∙}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' + HCl$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \leftrightarrow R \overset{∙}{\underset{∙ ∙}{O}} = CHR'$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \overset{C l_{2}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - CHClR' + C l^{∙}$

AIIMS - 2017

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323216 The presene of peroxides in old samples of ethers is detetced by shaking them with a freshly prepared solution of ${FeSO}_{4}$ followed by the addition of KCNS. The appearance of which colour indicates the presence of peroxides?

1 Blue

2 Green

3 Red

4 Brown

Explanation:

Due to the formation of $Fe (SCN)_{3}$ . Which is blood red colour substance.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323217 Which of the following cannot form Oxonium salts with diethyl ether?

1

HCl

2

HBr

3

H_{2} {SO}_{4}

4

HCN

Explanation:

$HCN$ is a weak acid.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323214 An organic compound $C_{3} H_{6} O$ does not give a precipitate with 2, 4-dinitrophenyl hydrazine reagent and does not react with sodium metal. It could be

1

{CH}_{3} - {CH}_{2} - CHO

2

{CH}_{3} - CO - {CH}_{3}

3

{CH}_{2} = CH - {CH}_{2} OH

4

{CH}_{2} = CH - {OCH}_{3}

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323215 In the presence of light, perchlorodiethyl ether is obtained from diethyl ether.
${(C_{2} H_{5})}_{2} O \overset{{Cl}_{2}}{⟶} {(C_{2} {Cl}_{5})}_{2} O$
The mechanism through which this reaction proceed is

1 Addition mechanism

2 Nucleophilic substitution mechanism

3 Free radical substitution mechanism

4 Elimination mechanism

Explanation:

The given reaction is,
${(C_{2} H_{5})}_{2} O \overset{C l_{2}}{\to} {(C_{2} C l_{5})}_{2} O$
The reaction proceeds by a free - radical mechanism and $α$ - substitution occurs readily because of resonance stabilisation of the intermediate.
$C l_{2} \overset{h υ}{\to} C l^{∙} + C l^{∙}$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - C H_{2} R' \overset{C l^{∙}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' + HCl$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \leftrightarrow R \overset{∙}{\underset{∙ ∙}{O}} = CHR'$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \overset{C l_{2}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - CHClR' + C l^{∙}$

AIIMS - 2017

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323216 The presene of peroxides in old samples of ethers is detetced by shaking them with a freshly prepared solution of ${FeSO}_{4}$ followed by the addition of KCNS. The appearance of which colour indicates the presence of peroxides?

1 Blue

2 Green

3 Red

4 Brown

Explanation:

Due to the formation of $Fe (SCN)_{3}$ . Which is blood red colour substance.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323217 Which of the following cannot form Oxonium salts with diethyl ether?

1

HCl

2

HBr

3

H_{2} {SO}_{4}

4

HCN

Explanation:

$HCN$ is a weak acid.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323214 An organic compound $C_{3} H_{6} O$ does not give a precipitate with 2, 4-dinitrophenyl hydrazine reagent and does not react with sodium metal. It could be

1

{CH}_{3} - {CH}_{2} - CHO

2

{CH}_{3} - CO - {CH}_{3}

3

{CH}_{2} = CH - {CH}_{2} OH

4

{CH}_{2} = CH - {OCH}_{3}

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323215 In the presence of light, perchlorodiethyl ether is obtained from diethyl ether.
${(C_{2} H_{5})}_{2} O \overset{{Cl}_{2}}{⟶} {(C_{2} {Cl}_{5})}_{2} O$
The mechanism through which this reaction proceed is

1 Addition mechanism

2 Nucleophilic substitution mechanism

3 Free radical substitution mechanism

4 Elimination mechanism

Explanation:

The given reaction is,
${(C_{2} H_{5})}_{2} O \overset{C l_{2}}{\to} {(C_{2} C l_{5})}_{2} O$
The reaction proceeds by a free - radical mechanism and $α$ - substitution occurs readily because of resonance stabilisation of the intermediate.
$C l_{2} \overset{h υ}{\to} C l^{∙} + C l^{∙}$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - C H_{2} R' \overset{C l^{∙}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' + HCl$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \leftrightarrow R \overset{∙}{\underset{∙ ∙}{O}} = CHR'$
$R \overset{∙ ∙}{\underset{∙ ∙}{O}} - \overset{∙}{C} HR' \overset{C l_{2}}{\to} R \overset{∙ ∙}{\underset{∙ ∙}{O}} - CHClR' + C l^{∙}$

AIIMS - 2017

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323216 The presene of peroxides in old samples of ethers is detetced by shaking them with a freshly prepared solution of ${FeSO}_{4}$ followed by the addition of KCNS. The appearance of which colour indicates the presence of peroxides?

1 Blue

2 Green

3 Red

4 Brown

Explanation:

Due to the formation of $Fe (SCN)_{3}$ . Which is blood red colour substance.

CHXII11:ALCOHOLS, PHENOLS AND ETHERS

323217 Which of the following cannot form Oxonium salts with diethyl ether?

1

HCl

2

HBr

3

H_{2} {SO}_{4}

4

HCN

Explanation:

$HCN$ is a weak acid.