QBManager

GENERAL ORGANIC CHEMISTRY

231506 The relative acidic strengths of benzoic acid, otoluic acid and p-toluic acid is of the decreasing order

1 o-toluic acid

>

p-toluic acid

>

benzoic acid

2 p-toluic acid

>

benzoic acid

>

o-toluic acid

3 o-toluic acid

>

benzoic acid

>

p-toluic acid

4 p-toluic acid

>

o-toluic acid

>

benzoic acid

Explanation:

+I-effect always decrease the acidity of carboxylic acid because +I-effect push the electron towards carboxylic group and the $- O - H$ bond is not easily break.
Hence the order of acidity is -
original image

Karnataka CET-2012

GENERAL ORGANIC CHEMISTRY

231507 Formic acid is a stronger acid than acetic acid. This can be explained using

1

+ M

effect

2 - I effect

3 + I effect

4

- M

effect

Explanation:

(C) :
original image
In acetic acid, methyl group release electron due to $+ I$ effect which decreases its acidic character whereas, formic acid does not contain any such type of group. Hence, formic acid is stronger acid than acetic acid.

Karnataka CET-2011

GENERAL ORGANIC CHEMISTRY

231529 Choose the weakest acid among the following

1

F_{3} C - COOH

2

F - {CH}_{2} - COOH

3

{CH}_{3} - COOH

4

{CH}_{3} - {CH}_{2} - COOH

5

{({CH}_{3})}_{2} CH - COOH

Explanation:

+I-effect decrease the acidity of carboxylic acid and -I-effect increase the acidity. Bulky alkyl group have higher $+ I$ -effect. Hence ${({CH}_{3})}_{2} CH - COOH$ is weakest acid. Hence option (e) is correct. The order of acidity is -
${({CH}_{3})}_{2} CHCOOH < {CH}_{3} {CH}_{2} COOH < {CH}_{3} COOH < F - {CH}_{2} COOH$

Kerala CEE-2010

GENERAL ORGANIC CHEMISTRY

231509 Which one of the following has the most nucleophilic nitrogen?

1

2

3

4

Explanation:

Nucleophiles are the species which have excess of electrons. Among the given species, the lone pair of nitrogen of pyrrole is involved in delocalisation of the ring, thus, are not available for donation. In aniline, the lone pair involved in conjugation with the $π$ electrons of the ring while in pyridine, these are relatively free for donation. Thus, nitrogen of pyridine is most nucleophilic.
original image
(phenyl and $- {COCH}_{3}$ both are electron withdrawing groups, thus decreases the nucleophilicity of nitrogen.

Karnataka CET

GENERAL ORGANIC CHEMISTRY

231513 Arrange the following in the increasing order of their basic strengths ${CH}_{3} {NH}_{2}, {({CH}_{3})}_{2} NH$ , ${({CH}_{3})}_{3} N, {NH}_{3}$

1

{NH}_{3} < {({CH}_{3})}_{3} N < {({CH}_{3})}_{2} NH < {CH}_{3} {NH}_{2}

2

{NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

3

{({CH}_{3})}_{3} N < {NH}_{3} < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

4

{CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH < {({CH}_{3})}_{3} N < {NH}_{3}

Explanation:

Aliphatic amines are more basic than ${NH}_{3}$ due to $+ I$ effect of alkyl groups. In aqueous medium tertiary amine is less basic than secondary amine because amine is less solvated as compared to the cation formed by protonation of tertiary amine is less solvates as compared to the cation formed by protonation of secondary amine. Hence, the increasing order of their basic strength is as :
${NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH$

2009]**

GENERAL ORGANIC CHEMISTRY

231506 The relative acidic strengths of benzoic acid, otoluic acid and p-toluic acid is of the decreasing order

1 o-toluic acid

>

p-toluic acid

>

benzoic acid

2 p-toluic acid

>

benzoic acid

>

o-toluic acid

3 o-toluic acid

>

benzoic acid

>

p-toluic acid

4 p-toluic acid

>

o-toluic acid

>

benzoic acid

Explanation:

+I-effect always decrease the acidity of carboxylic acid because +I-effect push the electron towards carboxylic group and the $- O - H$ bond is not easily break.
Hence the order of acidity is -
original image

Karnataka CET-2012

GENERAL ORGANIC CHEMISTRY

231507 Formic acid is a stronger acid than acetic acid. This can be explained using

1

+ M

effect

2 - I effect

3 + I effect

4

- M

effect

Explanation:

(C) :
original image
In acetic acid, methyl group release electron due to $+ I$ effect which decreases its acidic character whereas, formic acid does not contain any such type of group. Hence, formic acid is stronger acid than acetic acid.

Karnataka CET-2011

GENERAL ORGANIC CHEMISTRY

231529 Choose the weakest acid among the following

1

F_{3} C - COOH

2

F - {CH}_{2} - COOH

3

{CH}_{3} - COOH

4

{CH}_{3} - {CH}_{2} - COOH

5

{({CH}_{3})}_{2} CH - COOH

Explanation:

+I-effect decrease the acidity of carboxylic acid and -I-effect increase the acidity. Bulky alkyl group have higher $+ I$ -effect. Hence ${({CH}_{3})}_{2} CH - COOH$ is weakest acid. Hence option (e) is correct. The order of acidity is -
${({CH}_{3})}_{2} CHCOOH < {CH}_{3} {CH}_{2} COOH < {CH}_{3} COOH < F - {CH}_{2} COOH$

Kerala CEE-2010

GENERAL ORGANIC CHEMISTRY

231509 Which one of the following has the most nucleophilic nitrogen?

1

2

3

4

Explanation:

Nucleophiles are the species which have excess of electrons. Among the given species, the lone pair of nitrogen of pyrrole is involved in delocalisation of the ring, thus, are not available for donation. In aniline, the lone pair involved in conjugation with the $π$ electrons of the ring while in pyridine, these are relatively free for donation. Thus, nitrogen of pyridine is most nucleophilic.
original image
(phenyl and $- {COCH}_{3}$ both are electron withdrawing groups, thus decreases the nucleophilicity of nitrogen.

Karnataka CET

GENERAL ORGANIC CHEMISTRY

231513 Arrange the following in the increasing order of their basic strengths ${CH}_{3} {NH}_{2}, {({CH}_{3})}_{2} NH$ , ${({CH}_{3})}_{3} N, {NH}_{3}$

1

{NH}_{3} < {({CH}_{3})}_{3} N < {({CH}_{3})}_{2} NH < {CH}_{3} {NH}_{2}

2

{NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

3

{({CH}_{3})}_{3} N < {NH}_{3} < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

4

{CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH < {({CH}_{3})}_{3} N < {NH}_{3}

Explanation:

Aliphatic amines are more basic than ${NH}_{3}$ due to $+ I$ effect of alkyl groups. In aqueous medium tertiary amine is less basic than secondary amine because amine is less solvated as compared to the cation formed by protonation of tertiary amine is less solvates as compared to the cation formed by protonation of secondary amine. Hence, the increasing order of their basic strength is as :
${NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH$

2009]**

GENERAL ORGANIC CHEMISTRY

231506 The relative acidic strengths of benzoic acid, otoluic acid and p-toluic acid is of the decreasing order

1 o-toluic acid

>

p-toluic acid

>

benzoic acid

2 p-toluic acid

>

benzoic acid

>

o-toluic acid

3 o-toluic acid

>

benzoic acid

>

p-toluic acid

4 p-toluic acid

>

o-toluic acid

>

benzoic acid

Explanation:

+I-effect always decrease the acidity of carboxylic acid because +I-effect push the electron towards carboxylic group and the $- O - H$ bond is not easily break.
Hence the order of acidity is -
original image

Karnataka CET-2012

GENERAL ORGANIC CHEMISTRY

231507 Formic acid is a stronger acid than acetic acid. This can be explained using

1

+ M

effect

2 - I effect

3 + I effect

4

- M

effect

Explanation:

(C) :
original image
In acetic acid, methyl group release electron due to $+ I$ effect which decreases its acidic character whereas, formic acid does not contain any such type of group. Hence, formic acid is stronger acid than acetic acid.

Karnataka CET-2011

GENERAL ORGANIC CHEMISTRY

231529 Choose the weakest acid among the following

1

F_{3} C - COOH

2

F - {CH}_{2} - COOH

3

{CH}_{3} - COOH

4

{CH}_{3} - {CH}_{2} - COOH

5

{({CH}_{3})}_{2} CH - COOH

Explanation:

+I-effect decrease the acidity of carboxylic acid and -I-effect increase the acidity. Bulky alkyl group have higher $+ I$ -effect. Hence ${({CH}_{3})}_{2} CH - COOH$ is weakest acid. Hence option (e) is correct. The order of acidity is -
${({CH}_{3})}_{2} CHCOOH < {CH}_{3} {CH}_{2} COOH < {CH}_{3} COOH < F - {CH}_{2} COOH$

Kerala CEE-2010

GENERAL ORGANIC CHEMISTRY

231509 Which one of the following has the most nucleophilic nitrogen?

1

2

3

4

Explanation:

Nucleophiles are the species which have excess of electrons. Among the given species, the lone pair of nitrogen of pyrrole is involved in delocalisation of the ring, thus, are not available for donation. In aniline, the lone pair involved in conjugation with the $π$ electrons of the ring while in pyridine, these are relatively free for donation. Thus, nitrogen of pyridine is most nucleophilic.
original image
(phenyl and $- {COCH}_{3}$ both are electron withdrawing groups, thus decreases the nucleophilicity of nitrogen.

Karnataka CET

GENERAL ORGANIC CHEMISTRY

231513 Arrange the following in the increasing order of their basic strengths ${CH}_{3} {NH}_{2}, {({CH}_{3})}_{2} NH$ , ${({CH}_{3})}_{3} N, {NH}_{3}$

1

{NH}_{3} < {({CH}_{3})}_{3} N < {({CH}_{3})}_{2} NH < {CH}_{3} {NH}_{2}

2

{NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

3

{({CH}_{3})}_{3} N < {NH}_{3} < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

4

{CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH < {({CH}_{3})}_{3} N < {NH}_{3}

Explanation:

Aliphatic amines are more basic than ${NH}_{3}$ due to $+ I$ effect of alkyl groups. In aqueous medium tertiary amine is less basic than secondary amine because amine is less solvated as compared to the cation formed by protonation of tertiary amine is less solvates as compared to the cation formed by protonation of secondary amine. Hence, the increasing order of their basic strength is as :
${NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH$

2009]**

GENERAL ORGANIC CHEMISTRY

231506 The relative acidic strengths of benzoic acid, otoluic acid and p-toluic acid is of the decreasing order

1 o-toluic acid

>

p-toluic acid

>

benzoic acid

2 p-toluic acid

>

benzoic acid

>

o-toluic acid

3 o-toluic acid

>

benzoic acid

>

p-toluic acid

4 p-toluic acid

>

o-toluic acid

>

benzoic acid

Explanation:

+I-effect always decrease the acidity of carboxylic acid because +I-effect push the electron towards carboxylic group and the $- O - H$ bond is not easily break.
Hence the order of acidity is -
original image

Karnataka CET-2012

GENERAL ORGANIC CHEMISTRY

231507 Formic acid is a stronger acid than acetic acid. This can be explained using

1

+ M

effect

2 - I effect

3 + I effect

4

- M

effect

Explanation:

(C) :
original image
In acetic acid, methyl group release electron due to $+ I$ effect which decreases its acidic character whereas, formic acid does not contain any such type of group. Hence, formic acid is stronger acid than acetic acid.

Karnataka CET-2011

GENERAL ORGANIC CHEMISTRY

231529 Choose the weakest acid among the following

1

F_{3} C - COOH

2

F - {CH}_{2} - COOH

3

{CH}_{3} - COOH

4

{CH}_{3} - {CH}_{2} - COOH

5

{({CH}_{3})}_{2} CH - COOH

Explanation:

+I-effect decrease the acidity of carboxylic acid and -I-effect increase the acidity. Bulky alkyl group have higher $+ I$ -effect. Hence ${({CH}_{3})}_{2} CH - COOH$ is weakest acid. Hence option (e) is correct. The order of acidity is -
${({CH}_{3})}_{2} CHCOOH < {CH}_{3} {CH}_{2} COOH < {CH}_{3} COOH < F - {CH}_{2} COOH$

Kerala CEE-2010

GENERAL ORGANIC CHEMISTRY

231509 Which one of the following has the most nucleophilic nitrogen?

1

2

3

4

Explanation:

Nucleophiles are the species which have excess of electrons. Among the given species, the lone pair of nitrogen of pyrrole is involved in delocalisation of the ring, thus, are not available for donation. In aniline, the lone pair involved in conjugation with the $π$ electrons of the ring while in pyridine, these are relatively free for donation. Thus, nitrogen of pyridine is most nucleophilic.
original image
(phenyl and $- {COCH}_{3}$ both are electron withdrawing groups, thus decreases the nucleophilicity of nitrogen.

Karnataka CET

GENERAL ORGANIC CHEMISTRY

231513 Arrange the following in the increasing order of their basic strengths ${CH}_{3} {NH}_{2}, {({CH}_{3})}_{2} NH$ , ${({CH}_{3})}_{3} N, {NH}_{3}$

1

{NH}_{3} < {({CH}_{3})}_{3} N < {({CH}_{3})}_{2} NH < {CH}_{3} {NH}_{2}

2

{NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

3

{({CH}_{3})}_{3} N < {NH}_{3} < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

4

{CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH < {({CH}_{3})}_{3} N < {NH}_{3}

Explanation:

Aliphatic amines are more basic than ${NH}_{3}$ due to $+ I$ effect of alkyl groups. In aqueous medium tertiary amine is less basic than secondary amine because amine is less solvated as compared to the cation formed by protonation of tertiary amine is less solvates as compared to the cation formed by protonation of secondary amine. Hence, the increasing order of their basic strength is as :
${NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH$

2009]**

GENERAL ORGANIC CHEMISTRY

231506 The relative acidic strengths of benzoic acid, otoluic acid and p-toluic acid is of the decreasing order

1 o-toluic acid

>

p-toluic acid

>

benzoic acid

2 p-toluic acid

>

benzoic acid

>

o-toluic acid

3 o-toluic acid

>

benzoic acid

>

p-toluic acid

4 p-toluic acid

>

o-toluic acid

>

benzoic acid

Explanation:

+I-effect always decrease the acidity of carboxylic acid because +I-effect push the electron towards carboxylic group and the $- O - H$ bond is not easily break.
Hence the order of acidity is -
original image

Karnataka CET-2012

GENERAL ORGANIC CHEMISTRY

231507 Formic acid is a stronger acid than acetic acid. This can be explained using

1

+ M

effect

2 - I effect

3 + I effect

4

- M

effect

Explanation:

(C) :
original image
In acetic acid, methyl group release electron due to $+ I$ effect which decreases its acidic character whereas, formic acid does not contain any such type of group. Hence, formic acid is stronger acid than acetic acid.

Karnataka CET-2011

GENERAL ORGANIC CHEMISTRY

231529 Choose the weakest acid among the following

1

F_{3} C - COOH

2

F - {CH}_{2} - COOH

3

{CH}_{3} - COOH

4

{CH}_{3} - {CH}_{2} - COOH

5

{({CH}_{3})}_{2} CH - COOH

Explanation:

+I-effect decrease the acidity of carboxylic acid and -I-effect increase the acidity. Bulky alkyl group have higher $+ I$ -effect. Hence ${({CH}_{3})}_{2} CH - COOH$ is weakest acid. Hence option (e) is correct. The order of acidity is -
${({CH}_{3})}_{2} CHCOOH < {CH}_{3} {CH}_{2} COOH < {CH}_{3} COOH < F - {CH}_{2} COOH$

Kerala CEE-2010

GENERAL ORGANIC CHEMISTRY

231509 Which one of the following has the most nucleophilic nitrogen?

1

2

3

4

Explanation:

Nucleophiles are the species which have excess of electrons. Among the given species, the lone pair of nitrogen of pyrrole is involved in delocalisation of the ring, thus, are not available for donation. In aniline, the lone pair involved in conjugation with the $π$ electrons of the ring while in pyridine, these are relatively free for donation. Thus, nitrogen of pyridine is most nucleophilic.
original image
(phenyl and $- {COCH}_{3}$ both are electron withdrawing groups, thus decreases the nucleophilicity of nitrogen.

Karnataka CET

GENERAL ORGANIC CHEMISTRY

231513 Arrange the following in the increasing order of their basic strengths ${CH}_{3} {NH}_{2}, {({CH}_{3})}_{2} NH$ , ${({CH}_{3})}_{3} N, {NH}_{3}$

1

{NH}_{3} < {({CH}_{3})}_{3} N < {({CH}_{3})}_{2} NH < {CH}_{3} {NH}_{2}

2

{NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

3

{({CH}_{3})}_{3} N < {NH}_{3} < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH

4

{CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH < {({CH}_{3})}_{3} N < {NH}_{3}

Explanation:

Aliphatic amines are more basic than ${NH}_{3}$ due to $+ I$ effect of alkyl groups. In aqueous medium tertiary amine is less basic than secondary amine because amine is less solvated as compared to the cation formed by protonation of tertiary amine is less solvates as compared to the cation formed by protonation of secondary amine. Hence, the increasing order of their basic strength is as :
${NH}_{3} < {({CH}_{3})}_{3} N < {CH}_{3} {NH}_{2} < {({CH}_{3})}_{2} NH$

2009]**