QBManager

GENERAL ORGANIC CHEMISTRY

231576 The correct statement regarding electrophile is

1 Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile

2 Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile

3 Electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from nucleophile

4 Electrophile is a negatively changed species and can form a bond by accepting a pair of electrons from a nucleophile

Explanation:

Electrophile means that species which accept electron is known as electrophile. Electron accepted by vacant orbital or $(+)$ charge species. Hence the electrophiles is may be neutral may be $(+)$ charge species-
${BF}_{3}, {BH}_{3}, {AlCl}_{3}, {NO}_{2}^{+}, {Cl}^{\oplus}, {SO}_{3}$ . etc are electrophile that is it accept electron by nucleophile.

AIPMT -2007

GENERAL ORGANIC CHEMISTRY

231577 Which of the following statements is not correct for a nucleophile?

1 Ammonia is a nucleophile

2 Nucleophiles attack low

e^{-}

density sites.

3 Nucleophiles are not electron seeking

4 Nucleophile is a Lewis acid

Explanation:

(a) Ammonia is nucleophile because it have free lone pair electron.
(b) Nucleophiles attack at low $e^{⊖}$ density sites because nucleophile has already electron density.
(c) Nucleophiles are not electron seeking because nucleophiles have already electron density.
(d) Nucleophile is a lewis base not the lewis acid.

NEET-2015

GENERAL ORGANIC CHEMISTRY

231578 A tertiary butyl carbocation is more stable than a secondary butyl carbocation because of which of the following?

1

- I

effect of

- {CH}_{3}

groups

2

+ R

effect of

- {CH}_{3}

groups

3

- R

effect of

- {CH}_{3}

groups

4 Hyperconjugation

NEET-2020

GENERAL ORGANIC CHEMISTRY

231585 Which one of the following is least basic?

1

{NF}_{3}

2

{NCl}_{3}

3

{NBr}_{3}

4

{Nl}_{3}

Explanation:

Basic character of trihalides follows following decreasing order
${NI}_{3} > {NBr}_{3} > {NCl}_{3} > {NF}_{3}$
Hence, ${NF}_{3}$ is least basic.
Despite the presence of a lone pair of electrons on nitrogen, ${NF}_{3}$ does not act as Lewis base. There is no known compound in which it donates a pair of electrons to other reagents.

UP CPMT-2012

GENERAL ORGANIC CHEMISTRY

231576 The correct statement regarding electrophile is

1 Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile

2 Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile

3 Electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from nucleophile

4 Electrophile is a negatively changed species and can form a bond by accepting a pair of electrons from a nucleophile

Explanation:

Electrophile means that species which accept electron is known as electrophile. Electron accepted by vacant orbital or $(+)$ charge species. Hence the electrophiles is may be neutral may be $(+)$ charge species-
${BF}_{3}, {BH}_{3}, {AlCl}_{3}, {NO}_{2}^{+}, {Cl}^{\oplus}, {SO}_{3}$ . etc are electrophile that is it accept electron by nucleophile.

AIPMT -2007

GENERAL ORGANIC CHEMISTRY

231577 Which of the following statements is not correct for a nucleophile?

1 Ammonia is a nucleophile

2 Nucleophiles attack low

e^{-}

density sites.

3 Nucleophiles are not electron seeking

4 Nucleophile is a Lewis acid

Explanation:

(a) Ammonia is nucleophile because it have free lone pair electron.
(b) Nucleophiles attack at low $e^{⊖}$ density sites because nucleophile has already electron density.
(c) Nucleophiles are not electron seeking because nucleophiles have already electron density.
(d) Nucleophile is a lewis base not the lewis acid.

NEET-2015

GENERAL ORGANIC CHEMISTRY

231578 A tertiary butyl carbocation is more stable than a secondary butyl carbocation because of which of the following?

1

- I

effect of

- {CH}_{3}

groups

2

+ R

effect of

- {CH}_{3}

groups

3

- R

effect of

- {CH}_{3}

groups

4 Hyperconjugation

NEET-2020

GENERAL ORGANIC CHEMISTRY

231585 Which one of the following is least basic?

1

{NF}_{3}

2

{NCl}_{3}

3

{NBr}_{3}

4

{Nl}_{3}

Explanation:

Basic character of trihalides follows following decreasing order
${NI}_{3} > {NBr}_{3} > {NCl}_{3} > {NF}_{3}$
Hence, ${NF}_{3}$ is least basic.
Despite the presence of a lone pair of electrons on nitrogen, ${NF}_{3}$ does not act as Lewis base. There is no known compound in which it donates a pair of electrons to other reagents.

UP CPMT-2012

GENERAL ORGANIC CHEMISTRY

231576 The correct statement regarding electrophile is

1 Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile

2 Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile

3 Electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from nucleophile

4 Electrophile is a negatively changed species and can form a bond by accepting a pair of electrons from a nucleophile

Explanation:

Electrophile means that species which accept electron is known as electrophile. Electron accepted by vacant orbital or $(+)$ charge species. Hence the electrophiles is may be neutral may be $(+)$ charge species-
${BF}_{3}, {BH}_{3}, {AlCl}_{3}, {NO}_{2}^{+}, {Cl}^{\oplus}, {SO}_{3}$ . etc are electrophile that is it accept electron by nucleophile.

AIPMT -2007

GENERAL ORGANIC CHEMISTRY

231577 Which of the following statements is not correct for a nucleophile?

1 Ammonia is a nucleophile

2 Nucleophiles attack low

e^{-}

density sites.

3 Nucleophiles are not electron seeking

4 Nucleophile is a Lewis acid

Explanation:

(a) Ammonia is nucleophile because it have free lone pair electron.
(b) Nucleophiles attack at low $e^{⊖}$ density sites because nucleophile has already electron density.
(c) Nucleophiles are not electron seeking because nucleophiles have already electron density.
(d) Nucleophile is a lewis base not the lewis acid.

NEET-2015

GENERAL ORGANIC CHEMISTRY

231578 A tertiary butyl carbocation is more stable than a secondary butyl carbocation because of which of the following?

1

- I

effect of

- {CH}_{3}

groups

2

+ R

effect of

- {CH}_{3}

groups

3

- R

effect of

- {CH}_{3}

groups

4 Hyperconjugation

NEET-2020

GENERAL ORGANIC CHEMISTRY

231585 Which one of the following is least basic?

1

{NF}_{3}

2

{NCl}_{3}

3

{NBr}_{3}

4

{Nl}_{3}

Explanation:

Basic character of trihalides follows following decreasing order
${NI}_{3} > {NBr}_{3} > {NCl}_{3} > {NF}_{3}$
Hence, ${NF}_{3}$ is least basic.
Despite the presence of a lone pair of electrons on nitrogen, ${NF}_{3}$ does not act as Lewis base. There is no known compound in which it donates a pair of electrons to other reagents.

UP CPMT-2012

GENERAL ORGANIC CHEMISTRY

231576 The correct statement regarding electrophile is

1 Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile

2 Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile

3 Electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from nucleophile

4 Electrophile is a negatively changed species and can form a bond by accepting a pair of electrons from a nucleophile

Explanation:

Electrophile means that species which accept electron is known as electrophile. Electron accepted by vacant orbital or $(+)$ charge species. Hence the electrophiles is may be neutral may be $(+)$ charge species-
${BF}_{3}, {BH}_{3}, {AlCl}_{3}, {NO}_{2}^{+}, {Cl}^{\oplus}, {SO}_{3}$ . etc are electrophile that is it accept electron by nucleophile.

AIPMT -2007

GENERAL ORGANIC CHEMISTRY

231577 Which of the following statements is not correct for a nucleophile?

1 Ammonia is a nucleophile

2 Nucleophiles attack low

e^{-}

density sites.

3 Nucleophiles are not electron seeking

4 Nucleophile is a Lewis acid

Explanation:

(a) Ammonia is nucleophile because it have free lone pair electron.
(b) Nucleophiles attack at low $e^{⊖}$ density sites because nucleophile has already electron density.
(c) Nucleophiles are not electron seeking because nucleophiles have already electron density.
(d) Nucleophile is a lewis base not the lewis acid.

NEET-2015

GENERAL ORGANIC CHEMISTRY

231578 A tertiary butyl carbocation is more stable than a secondary butyl carbocation because of which of the following?

1

- I

effect of

- {CH}_{3}

groups

2

+ R

effect of

- {CH}_{3}

groups

3

- R

effect of

- {CH}_{3}

groups

4 Hyperconjugation

NEET-2020

GENERAL ORGANIC CHEMISTRY

231585 Which one of the following is least basic?

1

{NF}_{3}

2

{NCl}_{3}

3

{NBr}_{3}

4

{Nl}_{3}

Explanation:

Basic character of trihalides follows following decreasing order
${NI}_{3} > {NBr}_{3} > {NCl}_{3} > {NF}_{3}$
Hence, ${NF}_{3}$ is least basic.
Despite the presence of a lone pair of electrons on nitrogen, ${NF}_{3}$ does not act as Lewis base. There is no known compound in which it donates a pair of electrons to other reagents.

UP CPMT-2012