QBManager

GENERAL ORGANIC CHEMISTRY

231466 Which of the following species is a nucleophile?

1

\overset{+}{N} O_{2}

2

: {CX}_{2}

3

: {\ddot{N}}_{2}^{-}

4

\cdot {CH}_{3}

Explanation:

Nucleophiles are electron donating species. Among the given, only : ${\ddot{NH}}_{2}^{-}$ has a tendency to give lone pair of electrons, so it is a nucleophile.

JCECE - 2011

GENERAL ORGANIC CHEMISTRY

231472 The correct order of basic strength of the following are

1

2

3

4

Explanation:

$+ I$ effect increase the basicity and delocalization decrease the basicity. The carbonyl group delocalized the lone pair electron of N. Hence, it's decrease the basicity but in option ' $d$ ' original image group is attached at $- M$ -position which is not delocalized the lone pair electron of $N$ (only delocalized by phenyl group which is same for all) The order of basicity isIV $>$ III $>$ II $>$ I

JIPMER-2017

GENERAL ORGANIC CHEMISTRY

231480 Hyper conjugation is most useful for stabilizing which of the following carboctions?

1 Neo-pentyl

2 Tert-butyl

3 Iso-propy

4 Ethyl

Explanation:

We know that in electrophilic aromatic substitution, the nitrogroup is an electron withdrawing group which decreases electron density at metaposition. Therefore ${NO}_{2}$ group is meta directing.

JIPMER-2011

GENERAL ORGANIC CHEMISTRY

231481 Which of the following statements is correct?

1 + I effect stabilizes a carbanion

2 + I effect stabilizes a carbocation

3 - I effect stabilizes a carbanion

4 - I effect stabilizes a carbocation

Explanation:

Positive inductive effect (+I effect) is arises due to electron releasing group $(y)$ . $+ I$ group stabilizes carbocation due to dispersion of positive charge on the + I effect group also.

BCECE-2013

GENERAL ORGANIC CHEMISTRY

231466 Which of the following species is a nucleophile?

1

\overset{+}{N} O_{2}

2

: {CX}_{2}

3

: {\ddot{N}}_{2}^{-}

4

\cdot {CH}_{3}

Explanation:

Nucleophiles are electron donating species. Among the given, only : ${\ddot{NH}}_{2}^{-}$ has a tendency to give lone pair of electrons, so it is a nucleophile.

JCECE - 2011

GENERAL ORGANIC CHEMISTRY

231472 The correct order of basic strength of the following are

1

2

3

4

Explanation:

$+ I$ effect increase the basicity and delocalization decrease the basicity. The carbonyl group delocalized the lone pair electron of N. Hence, it's decrease the basicity but in option ' $d$ ' original image group is attached at $- M$ -position which is not delocalized the lone pair electron of $N$ (only delocalized by phenyl group which is same for all) The order of basicity isIV $>$ III $>$ II $>$ I

JIPMER-2017

GENERAL ORGANIC CHEMISTRY

231480 Hyper conjugation is most useful for stabilizing which of the following carboctions?

1 Neo-pentyl

2 Tert-butyl

3 Iso-propy

4 Ethyl

Explanation:

We know that in electrophilic aromatic substitution, the nitrogroup is an electron withdrawing group which decreases electron density at metaposition. Therefore ${NO}_{2}$ group is meta directing.

JIPMER-2011

GENERAL ORGANIC CHEMISTRY

231481 Which of the following statements is correct?

1 + I effect stabilizes a carbanion

2 + I effect stabilizes a carbocation

3 - I effect stabilizes a carbanion

4 - I effect stabilizes a carbocation

Explanation:

Positive inductive effect (+I effect) is arises due to electron releasing group $(y)$ . $+ I$ group stabilizes carbocation due to dispersion of positive charge on the + I effect group also.

BCECE-2013

GENERAL ORGANIC CHEMISTRY

231466 Which of the following species is a nucleophile?

1

\overset{+}{N} O_{2}

2

: {CX}_{2}

3

: {\ddot{N}}_{2}^{-}

4

\cdot {CH}_{3}

Explanation:

Nucleophiles are electron donating species. Among the given, only : ${\ddot{NH}}_{2}^{-}$ has a tendency to give lone pair of electrons, so it is a nucleophile.

JCECE - 2011

GENERAL ORGANIC CHEMISTRY

231472 The correct order of basic strength of the following are

1

2

3

4

Explanation:

$+ I$ effect increase the basicity and delocalization decrease the basicity. The carbonyl group delocalized the lone pair electron of N. Hence, it's decrease the basicity but in option ' $d$ ' original image group is attached at $- M$ -position which is not delocalized the lone pair electron of $N$ (only delocalized by phenyl group which is same for all) The order of basicity isIV $>$ III $>$ II $>$ I

JIPMER-2017

GENERAL ORGANIC CHEMISTRY

231480 Hyper conjugation is most useful for stabilizing which of the following carboctions?

1 Neo-pentyl

2 Tert-butyl

3 Iso-propy

4 Ethyl

Explanation:

We know that in electrophilic aromatic substitution, the nitrogroup is an electron withdrawing group which decreases electron density at metaposition. Therefore ${NO}_{2}$ group is meta directing.

JIPMER-2011

GENERAL ORGANIC CHEMISTRY

231481 Which of the following statements is correct?

1 + I effect stabilizes a carbanion

2 + I effect stabilizes a carbocation

3 - I effect stabilizes a carbanion

4 - I effect stabilizes a carbocation

Explanation:

Positive inductive effect (+I effect) is arises due to electron releasing group $(y)$ . $+ I$ group stabilizes carbocation due to dispersion of positive charge on the + I effect group also.

BCECE-2013

GENERAL ORGANIC CHEMISTRY

231466 Which of the following species is a nucleophile?

1

\overset{+}{N} O_{2}

2

: {CX}_{2}

3

: {\ddot{N}}_{2}^{-}

4

\cdot {CH}_{3}

Explanation:

Nucleophiles are electron donating species. Among the given, only : ${\ddot{NH}}_{2}^{-}$ has a tendency to give lone pair of electrons, so it is a nucleophile.

JCECE - 2011

GENERAL ORGANIC CHEMISTRY

231472 The correct order of basic strength of the following are

1

2

3

4

Explanation:

$+ I$ effect increase the basicity and delocalization decrease the basicity. The carbonyl group delocalized the lone pair electron of N. Hence, it's decrease the basicity but in option ' $d$ ' original image group is attached at $- M$ -position which is not delocalized the lone pair electron of $N$ (only delocalized by phenyl group which is same for all) The order of basicity isIV $>$ III $>$ II $>$ I

JIPMER-2017

GENERAL ORGANIC CHEMISTRY

231480 Hyper conjugation is most useful for stabilizing which of the following carboctions?

1 Neo-pentyl

2 Tert-butyl

3 Iso-propy

4 Ethyl

Explanation:

We know that in electrophilic aromatic substitution, the nitrogroup is an electron withdrawing group which decreases electron density at metaposition. Therefore ${NO}_{2}$ group is meta directing.

JIPMER-2011

GENERAL ORGANIC CHEMISTRY

231481 Which of the following statements is correct?

1 + I effect stabilizes a carbanion

2 + I effect stabilizes a carbocation

3 - I effect stabilizes a carbanion

4 - I effect stabilizes a carbocation

Explanation:

Positive inductive effect (+I effect) is arises due to electron releasing group $(y)$ . $+ I$ group stabilizes carbocation due to dispersion of positive charge on the + I effect group also.

BCECE-2013