化学的几个问题

taociUID: 2124956

1，什么是Wurtz inversion？说是用于制备对称烷烃。

2，什么是Relaxation method？可以用于研究什么？

3，问个题干的意思。“The energy of a molecule between two phases is intermediate between that of the free molecule and that of the molecule in the bulk. Its potential energy would be reduced if it is moved into the bulk thus, molecules are under the influence of a force which tends to draw them into the bulk. This force is called what?"

4，The nucleophilic aromatic substitution that can occur on a benzene ring is affected by the substituent group(s) present. Which one of the following statements correctly describes such a substituent group and its effects.
(a) -CN, electron withdrawing, destabilizes carbanion;
(b) -COOH, electron releasing, activates the ring;
(c) -NO2, stabilizes carbanion, activates the ring;
(d) -R, destabilizes carbanion, electron withdrawing;
(e) -CHO, deactivates the ring, destabilizes carbanion.

xenonUID: 2149750

4 吸电子基引起活化，选c

[ Last edited by xenon on 2005-11-11 at 11:12 ]

cindyzhuUID: 2109805

第4题什么意思？芳香环怎么发生亲核取代反应了？应该是亲电取代啊，题目就看不明白！

cindyzhuUID: 2109805

我觉得选C

xenonUID: 2149750

笔误，选C，不好意思，呵呵

taociUID: 2124956

硝基氯苯上的氯被氨取代，是不是一个芳环亲核取代反应？

可不可以这样说，芳环亲核取代的取代基活化钝化效应正好和亲电相反？

xenonUID: 2149750

是

可以，芳香亲核取代反映中，环上有吸电子集团引起活化，推电子集团引起钝化

西西西西UID: 186753

第二个就是驰域法撒

anluoluoUID: 2116225

2，什么是Relaxation method？可以用于研究什么？

fast reaction

3，问个题干的意思。“The energy of a molecule between two phases is intermediate between that of the free molecule and that of the molecule in the bulk. Its potential energy would be reduced if it is moved into the bulk thus, molecules are under the influence of a force which tends to draw them into the bulk. This force is called what?"

Surface tension

4，The nucleophilic aromatic substitution that can occur on a benzene ring is affected by the substituent group(s) present. Which one of the following statements correctly describes such a substituent group and its effects.
(a) -CN, electron withdrawing, destabilizes carbanion;
(b) -COOH, electron releasing, activates the ring;
(c) -NO2, stabilizes carbanion, activates the ring;
(d) -R, destabilizes carbanion, electron withdrawing;
(e) -CHO, deactivates the ring, destabilizes carbanion.

The nucleophilic aromatic substitution   is not the same as the
The nucleophilic aromatic substitution

NO2, stabilizes carbanion, activates the ring

anluoluoUID: 2116225

sorry
The nucleophilic aromatic substitution is not the same as the The electrophilic aromatic substitution


we are familiar with F-C The electrophilic aromatic substitution :
CH3-CO-CL + Ph ----  PhCOCH3