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CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323607 A cyanohydrin of a compound (X) on hydrolysis gives an $α$ -hydroxy acid which shows optical activity after resolution. The compound $(X)$ is

1 Acetone

2 Formaldehyde

3 Diethyl ketone

4 Acetaldehyde

Explanation:

Acetaldehyde reacts with $KCN$ in acidic medium to form cyanohydrin. It on acid hydrolysis yields lactic acid which is optically active.
supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323608 Study the mechanism given below carefully:
supporting img

Select the correct statement for the above diagram from the options given below.

1 A nucleophile attacks the electrophilic carbon of the polar carbonyl group from direction parallel to the plane of

{sp}^{2}

hybridized orbitals of carbonyl carbon.

2 The hybridization of carbon changes from sp to

{sp}^{2}

in this process.

3 The net result is the addition of nucleophile and

H^{+}

across the carbon-oxygen double bond.

4 Step (2) is rate determination step.

Explanation:

Nucleophile attacks the electrophilic carbon group in direction perpendicular to the carbonyl group and its hybridization changes from ${sp}^{2}$ to ${sp}^{3}$ and slow step is the rate determining step.

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323609 The order of reactivity of phenyl magnesium bromide ( $PhMgBr$ ) with the following compounds :
supporting img

1 III

>

II

>

I

2 II

>

I

>

III

3 I

>

III

>

II

4 I

>

II

>

III

Explanation:

Since, alkyl group has $+ I$ effect and aryl group has $+ R$ effect, thus greater the number of alkyl and aryl groups attached to the carbonyl group, its reactivity towards nucleophilic addition reaction decreases. Secondly, as the steric crowding on carbonyl group increases, the reactivity decreases accordingly.
$∴$ Correct reactivity order for reaction with $PhMgBr$ is

supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323610 Match the column I (structure) with the column II (name) and mark the appropriate choice.
supporting img

1 A - Q, B - S, C - P, D - R

2 A - R, B - P, C - S, D - Q

3 A - R, B - S, C - P, D - Q

4 A - S, B - R, C - Q, D - P

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323607 A cyanohydrin of a compound (X) on hydrolysis gives an $α$ -hydroxy acid which shows optical activity after resolution. The compound $(X)$ is

1 Acetone

2 Formaldehyde

3 Diethyl ketone

4 Acetaldehyde

Explanation:

Acetaldehyde reacts with $KCN$ in acidic medium to form cyanohydrin. It on acid hydrolysis yields lactic acid which is optically active.
supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323608 Study the mechanism given below carefully:
supporting img

Select the correct statement for the above diagram from the options given below.

1 A nucleophile attacks the electrophilic carbon of the polar carbonyl group from direction parallel to the plane of

{sp}^{2}

hybridized orbitals of carbonyl carbon.

2 The hybridization of carbon changes from sp to

{sp}^{2}

in this process.

3 The net result is the addition of nucleophile and

H^{+}

across the carbon-oxygen double bond.

4 Step (2) is rate determination step.

Explanation:

Nucleophile attacks the electrophilic carbon group in direction perpendicular to the carbonyl group and its hybridization changes from ${sp}^{2}$ to ${sp}^{3}$ and slow step is the rate determining step.

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323609 The order of reactivity of phenyl magnesium bromide ( $PhMgBr$ ) with the following compounds :
supporting img

1 III

>

II

>

I

2 II

>

I

>

III

3 I

>

III

>

II

4 I

>

II

>

III

Explanation:

Since, alkyl group has $+ I$ effect and aryl group has $+ R$ effect, thus greater the number of alkyl and aryl groups attached to the carbonyl group, its reactivity towards nucleophilic addition reaction decreases. Secondly, as the steric crowding on carbonyl group increases, the reactivity decreases accordingly.
$∴$ Correct reactivity order for reaction with $PhMgBr$ is

supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323610 Match the column I (structure) with the column II (name) and mark the appropriate choice.
supporting img

1 A - Q, B - S, C - P, D - R

2 A - R, B - P, C - S, D - Q

3 A - R, B - S, C - P, D - Q

4 A - S, B - R, C - Q, D - P

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323607 A cyanohydrin of a compound (X) on hydrolysis gives an $α$ -hydroxy acid which shows optical activity after resolution. The compound $(X)$ is

1 Acetone

2 Formaldehyde

3 Diethyl ketone

4 Acetaldehyde

Explanation:

Acetaldehyde reacts with $KCN$ in acidic medium to form cyanohydrin. It on acid hydrolysis yields lactic acid which is optically active.
supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323608 Study the mechanism given below carefully:
supporting img

Select the correct statement for the above diagram from the options given below.

1 A nucleophile attacks the electrophilic carbon of the polar carbonyl group from direction parallel to the plane of

{sp}^{2}

hybridized orbitals of carbonyl carbon.

2 The hybridization of carbon changes from sp to

{sp}^{2}

in this process.

3 The net result is the addition of nucleophile and

H^{+}

across the carbon-oxygen double bond.

4 Step (2) is rate determination step.

Explanation:

Nucleophile attacks the electrophilic carbon group in direction perpendicular to the carbonyl group and its hybridization changes from ${sp}^{2}$ to ${sp}^{3}$ and slow step is the rate determining step.

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323609 The order of reactivity of phenyl magnesium bromide ( $PhMgBr$ ) with the following compounds :
supporting img

1 III

>

II

>

I

2 II

>

I

>

III

3 I

>

III

>

II

4 I

>

II

>

III

Explanation:

Since, alkyl group has $+ I$ effect and aryl group has $+ R$ effect, thus greater the number of alkyl and aryl groups attached to the carbonyl group, its reactivity towards nucleophilic addition reaction decreases. Secondly, as the steric crowding on carbonyl group increases, the reactivity decreases accordingly.
$∴$ Correct reactivity order for reaction with $PhMgBr$ is

supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323610 Match the column I (structure) with the column II (name) and mark the appropriate choice.
supporting img

1 A - Q, B - S, C - P, D - R

2 A - R, B - P, C - S, D - Q

3 A - R, B - S, C - P, D - Q

4 A - S, B - R, C - Q, D - P

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323607 A cyanohydrin of a compound (X) on hydrolysis gives an $α$ -hydroxy acid which shows optical activity after resolution. The compound $(X)$ is

1 Acetone

2 Formaldehyde

3 Diethyl ketone

4 Acetaldehyde

Explanation:

Acetaldehyde reacts with $KCN$ in acidic medium to form cyanohydrin. It on acid hydrolysis yields lactic acid which is optically active.
supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323608 Study the mechanism given below carefully:
supporting img

Select the correct statement for the above diagram from the options given below.

1 A nucleophile attacks the electrophilic carbon of the polar carbonyl group from direction parallel to the plane of

{sp}^{2}

hybridized orbitals of carbonyl carbon.

2 The hybridization of carbon changes from sp to

{sp}^{2}

in this process.

3 The net result is the addition of nucleophile and

H^{+}

across the carbon-oxygen double bond.

4 Step (2) is rate determination step.

Explanation:

Nucleophile attacks the electrophilic carbon group in direction perpendicular to the carbonyl group and its hybridization changes from ${sp}^{2}$ to ${sp}^{3}$ and slow step is the rate determining step.

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323609 The order of reactivity of phenyl magnesium bromide ( $PhMgBr$ ) with the following compounds :
supporting img

1 III

>

II

>

I

2 II

>

I

>

III

3 I

>

III

>

II

4 I

>

II

>

III

Explanation:

Since, alkyl group has $+ I$ effect and aryl group has $+ R$ effect, thus greater the number of alkyl and aryl groups attached to the carbonyl group, its reactivity towards nucleophilic addition reaction decreases. Secondly, as the steric crowding on carbonyl group increases, the reactivity decreases accordingly.
$∴$ Correct reactivity order for reaction with $PhMgBr$ is

supporting img

CHXII12:ALDEHYDES KETONES AND CARBOXYLIC ACIDS

323610 Match the column I (structure) with the column II (name) and mark the appropriate choice.
supporting img

1 A - Q, B - S, C - P, D - R

2 A - R, B - P, C - S, D - Q

3 A - R, B - S, C - P, D - Q

4 A - S, B - R, C - Q, D - P

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