322817
Which one is least reactive towards nucleophilic substitution reaction?
1 o-aminochlorobenzene
2 Chlorobenzene
3 o-nitrochlorobenzene
4 2, 4-dinitrochlorobenzene
Explanation:
In nucleophilic substitution, for aromatic compounds like benzene, nucleophile displaces a good leaving group like halide on aromatic ring. Electron withdrawing groups also activate the ring towards nucleophilic attack. For e.g. nitro group at ortho and para-position, halide in 2, 4-dinitrochlorobenzene. In 2, 4-dinitrochlorobenzene, nitro group is present at ortho and para-position and activates the ring. But electron donating groups like- \(\mathrm{NH}_{2}\) (if at ortho,para-position) will decrease the nucleophilic substitution reaction. Hence, (1) is the correct option.
CHXII10:HALOALKANES AND HALOARENES
322818
Assertion : Aryl halides undergo nucleophilic substitution with ease. Reason : Hybridisation of C-atom attached to halide is \(\mathrm{sp}^{3}\) - hybrid
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
Both A and R are false as, aryl halides undergo nucleophilic substitution with great difficulty due to partial double bond character between \(\mathrm{C}\) - atom of ring and halide atom. Also, hybridisation of \(\mathrm{C}\) - atom attached to halogen is \(\mathrm{sp}^{2}\) - hybridisation.
AIIMS - 2017
CHXII10:HALOALKANES AND HALOARENES
322819
Aryl halides are extremely less reactive towards nucleophilic substitution. Predict the order of reactivity of the following compounds towards nucleophilic substitution
1 III \(>\) II \(>\) I
2 II \(>\) III \(>\) I
3 I \(>\) II \(>\) III
4 I \(>\) III \(>\) II
Explanation:
More number of EWG more is reactivity towards \(\mathrm{S}_{\mathrm{N}}{ }^{\mathrm{Ar}}\)
CHXII10:HALOALKANES AND HALOARENES
322820
Increasing order towards nucleophilic substitution among given compounds
1 (i) \( < \) (ii) \( < \) (iii)
2 (i) \( < \) (iii) \( < \) (ii)
3 (iii) \( < \) (ii) \( < \) (i)
4 (ii) \( < \) (iii) \( < \) (i)
Explanation:
The rate of nucleophilic substitution reaction decreases in presence of electron releasing group at ortho or para position. So, correct order is I \(>\) III \(>\) II \(\left(\mathrm{CH}_{3}\right.\) is \(+\mathrm{I}\) and hyper conjugation group).
CHXII10:HALOALKANES AND HALOARENES
322821
Assertion : Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution. Reason : Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
322817
Which one is least reactive towards nucleophilic substitution reaction?
1 o-aminochlorobenzene
2 Chlorobenzene
3 o-nitrochlorobenzene
4 2, 4-dinitrochlorobenzene
Explanation:
In nucleophilic substitution, for aromatic compounds like benzene, nucleophile displaces a good leaving group like halide on aromatic ring. Electron withdrawing groups also activate the ring towards nucleophilic attack. For e.g. nitro group at ortho and para-position, halide in 2, 4-dinitrochlorobenzene. In 2, 4-dinitrochlorobenzene, nitro group is present at ortho and para-position and activates the ring. But electron donating groups like- \(\mathrm{NH}_{2}\) (if at ortho,para-position) will decrease the nucleophilic substitution reaction. Hence, (1) is the correct option.
CHXII10:HALOALKANES AND HALOARENES
322818
Assertion : Aryl halides undergo nucleophilic substitution with ease. Reason : Hybridisation of C-atom attached to halide is \(\mathrm{sp}^{3}\) - hybrid
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
Both A and R are false as, aryl halides undergo nucleophilic substitution with great difficulty due to partial double bond character between \(\mathrm{C}\) - atom of ring and halide atom. Also, hybridisation of \(\mathrm{C}\) - atom attached to halogen is \(\mathrm{sp}^{2}\) - hybridisation.
AIIMS - 2017
CHXII10:HALOALKANES AND HALOARENES
322819
Aryl halides are extremely less reactive towards nucleophilic substitution. Predict the order of reactivity of the following compounds towards nucleophilic substitution
1 III \(>\) II \(>\) I
2 II \(>\) III \(>\) I
3 I \(>\) II \(>\) III
4 I \(>\) III \(>\) II
Explanation:
More number of EWG more is reactivity towards \(\mathrm{S}_{\mathrm{N}}{ }^{\mathrm{Ar}}\)
CHXII10:HALOALKANES AND HALOARENES
322820
Increasing order towards nucleophilic substitution among given compounds
1 (i) \( < \) (ii) \( < \) (iii)
2 (i) \( < \) (iii) \( < \) (ii)
3 (iii) \( < \) (ii) \( < \) (i)
4 (ii) \( < \) (iii) \( < \) (i)
Explanation:
The rate of nucleophilic substitution reaction decreases in presence of electron releasing group at ortho or para position. So, correct order is I \(>\) III \(>\) II \(\left(\mathrm{CH}_{3}\right.\) is \(+\mathrm{I}\) and hyper conjugation group).
CHXII10:HALOALKANES AND HALOARENES
322821
Assertion : Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution. Reason : Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
322817
Which one is least reactive towards nucleophilic substitution reaction?
1 o-aminochlorobenzene
2 Chlorobenzene
3 o-nitrochlorobenzene
4 2, 4-dinitrochlorobenzene
Explanation:
In nucleophilic substitution, for aromatic compounds like benzene, nucleophile displaces a good leaving group like halide on aromatic ring. Electron withdrawing groups also activate the ring towards nucleophilic attack. For e.g. nitro group at ortho and para-position, halide in 2, 4-dinitrochlorobenzene. In 2, 4-dinitrochlorobenzene, nitro group is present at ortho and para-position and activates the ring. But electron donating groups like- \(\mathrm{NH}_{2}\) (if at ortho,para-position) will decrease the nucleophilic substitution reaction. Hence, (1) is the correct option.
CHXII10:HALOALKANES AND HALOARENES
322818
Assertion : Aryl halides undergo nucleophilic substitution with ease. Reason : Hybridisation of C-atom attached to halide is \(\mathrm{sp}^{3}\) - hybrid
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
Both A and R are false as, aryl halides undergo nucleophilic substitution with great difficulty due to partial double bond character between \(\mathrm{C}\) - atom of ring and halide atom. Also, hybridisation of \(\mathrm{C}\) - atom attached to halogen is \(\mathrm{sp}^{2}\) - hybridisation.
AIIMS - 2017
CHXII10:HALOALKANES AND HALOARENES
322819
Aryl halides are extremely less reactive towards nucleophilic substitution. Predict the order of reactivity of the following compounds towards nucleophilic substitution
1 III \(>\) II \(>\) I
2 II \(>\) III \(>\) I
3 I \(>\) II \(>\) III
4 I \(>\) III \(>\) II
Explanation:
More number of EWG more is reactivity towards \(\mathrm{S}_{\mathrm{N}}{ }^{\mathrm{Ar}}\)
CHXII10:HALOALKANES AND HALOARENES
322820
Increasing order towards nucleophilic substitution among given compounds
1 (i) \( < \) (ii) \( < \) (iii)
2 (i) \( < \) (iii) \( < \) (ii)
3 (iii) \( < \) (ii) \( < \) (i)
4 (ii) \( < \) (iii) \( < \) (i)
Explanation:
The rate of nucleophilic substitution reaction decreases in presence of electron releasing group at ortho or para position. So, correct order is I \(>\) III \(>\) II \(\left(\mathrm{CH}_{3}\right.\) is \(+\mathrm{I}\) and hyper conjugation group).
CHXII10:HALOALKANES AND HALOARENES
322821
Assertion : Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution. Reason : Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
322817
Which one is least reactive towards nucleophilic substitution reaction?
1 o-aminochlorobenzene
2 Chlorobenzene
3 o-nitrochlorobenzene
4 2, 4-dinitrochlorobenzene
Explanation:
In nucleophilic substitution, for aromatic compounds like benzene, nucleophile displaces a good leaving group like halide on aromatic ring. Electron withdrawing groups also activate the ring towards nucleophilic attack. For e.g. nitro group at ortho and para-position, halide in 2, 4-dinitrochlorobenzene. In 2, 4-dinitrochlorobenzene, nitro group is present at ortho and para-position and activates the ring. But electron donating groups like- \(\mathrm{NH}_{2}\) (if at ortho,para-position) will decrease the nucleophilic substitution reaction. Hence, (1) is the correct option.
CHXII10:HALOALKANES AND HALOARENES
322818
Assertion : Aryl halides undergo nucleophilic substitution with ease. Reason : Hybridisation of C-atom attached to halide is \(\mathrm{sp}^{3}\) - hybrid
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
Both A and R are false as, aryl halides undergo nucleophilic substitution with great difficulty due to partial double bond character between \(\mathrm{C}\) - atom of ring and halide atom. Also, hybridisation of \(\mathrm{C}\) - atom attached to halogen is \(\mathrm{sp}^{2}\) - hybridisation.
AIIMS - 2017
CHXII10:HALOALKANES AND HALOARENES
322819
Aryl halides are extremely less reactive towards nucleophilic substitution. Predict the order of reactivity of the following compounds towards nucleophilic substitution
1 III \(>\) II \(>\) I
2 II \(>\) III \(>\) I
3 I \(>\) II \(>\) III
4 I \(>\) III \(>\) II
Explanation:
More number of EWG more is reactivity towards \(\mathrm{S}_{\mathrm{N}}{ }^{\mathrm{Ar}}\)
CHXII10:HALOALKANES AND HALOARENES
322820
Increasing order towards nucleophilic substitution among given compounds
1 (i) \( < \) (ii) \( < \) (iii)
2 (i) \( < \) (iii) \( < \) (ii)
3 (iii) \( < \) (ii) \( < \) (i)
4 (ii) \( < \) (iii) \( < \) (i)
Explanation:
The rate of nucleophilic substitution reaction decreases in presence of electron releasing group at ortho or para position. So, correct order is I \(>\) III \(>\) II \(\left(\mathrm{CH}_{3}\right.\) is \(+\mathrm{I}\) and hyper conjugation group).
CHXII10:HALOALKANES AND HALOARENES
322821
Assertion : Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution. Reason : Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
322817
Which one is least reactive towards nucleophilic substitution reaction?
1 o-aminochlorobenzene
2 Chlorobenzene
3 o-nitrochlorobenzene
4 2, 4-dinitrochlorobenzene
Explanation:
In nucleophilic substitution, for aromatic compounds like benzene, nucleophile displaces a good leaving group like halide on aromatic ring. Electron withdrawing groups also activate the ring towards nucleophilic attack. For e.g. nitro group at ortho and para-position, halide in 2, 4-dinitrochlorobenzene. In 2, 4-dinitrochlorobenzene, nitro group is present at ortho and para-position and activates the ring. But electron donating groups like- \(\mathrm{NH}_{2}\) (if at ortho,para-position) will decrease the nucleophilic substitution reaction. Hence, (1) is the correct option.
CHXII10:HALOALKANES AND HALOARENES
322818
Assertion : Aryl halides undergo nucleophilic substitution with ease. Reason : Hybridisation of C-atom attached to halide is \(\mathrm{sp}^{3}\) - hybrid
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Both Assertion and Reason are incorrect.
Explanation:
Both A and R are false as, aryl halides undergo nucleophilic substitution with great difficulty due to partial double bond character between \(\mathrm{C}\) - atom of ring and halide atom. Also, hybridisation of \(\mathrm{C}\) - atom attached to halogen is \(\mathrm{sp}^{2}\) - hybridisation.
AIIMS - 2017
CHXII10:HALOALKANES AND HALOARENES
322819
Aryl halides are extremely less reactive towards nucleophilic substitution. Predict the order of reactivity of the following compounds towards nucleophilic substitution
1 III \(>\) II \(>\) I
2 II \(>\) III \(>\) I
3 I \(>\) II \(>\) III
4 I \(>\) III \(>\) II
Explanation:
More number of EWG more is reactivity towards \(\mathrm{S}_{\mathrm{N}}{ }^{\mathrm{Ar}}\)
CHXII10:HALOALKANES AND HALOARENES
322820
Increasing order towards nucleophilic substitution among given compounds
1 (i) \( < \) (ii) \( < \) (iii)
2 (i) \( < \) (iii) \( < \) (ii)
3 (iii) \( < \) (ii) \( < \) (i)
4 (ii) \( < \) (iii) \( < \) (i)
Explanation:
The rate of nucleophilic substitution reaction decreases in presence of electron releasing group at ortho or para position. So, correct order is I \(>\) III \(>\) II \(\left(\mathrm{CH}_{3}\right.\) is \(+\mathrm{I}\) and hyper conjugation group).
CHXII10:HALOALKANES AND HALOARENES
322821
Assertion : Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution. Reason : Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
