GyanMul PrepLearn • Prepare • Grow • Together

GyanMul Prep · NEB +2 · Science · Grade 12

Chemistry (Science, Grade 12)

Everything on these tabs is Chemistry (Science, Grade 12) only, within NEB +2 Science · Grade 12.

Science · Grade 12 subjects

GyanMul Prep · NEB +2 · Science · Grade 12

Chemistry (Science, Grade 12)

Everything on these tabs is Chemistry (Science, Grade 12) only, within NEB +2 Science · Grade 12.

Science · Grade 12 subjects

Chapter 9 of 21 · Chemistry (Science, Grade 12)

Haloarenes

8 topics
Board exam — Organic chemistry, 33 marks across 10 chapters

The same bond on a benzene ring, and why it behaves so differently: resonance gives it partial double bond character, so the halogen will not leave — while the ring it sits on keeps directing new groups ortho and para.

Topics

What the syllabus defines for this chapter

1Nomenclature and classification of haloarenes
2Preparation from benzene, from phenol, and by Sandmeyer's and Gattermann's reactions
3Physical properties
4Low reactivity towards nucleophilic substitution; resonance and partial double bond character
5Nucleophilic substitution under forcing conditions
6Electrophilic substitution; the halogen as an ortho- and para-directing deactivator
7Wurtz-Fittig and Fittig reactions
8Uses: DDT, BHC and chlorobenzene