Match the items of Column I and Column II. Column I Column II (i) S N 1 reaction (a) vic-dibromides (ii) Chemicals in fire extinguisher (b) gem-dihalides (iii) Bromination of alkenes (c) Racemisation (iv) Alkylidene halides (d) Saytzeff rule (v) Elimination of HX from alkyl halide (e) Chlorobromocarbons

(i) S N 1 reaction is accompanied by racemisation. The carbocation formed in the slow step being sp 2 hybridised is planar and attack of nucleophile may take place from either side resulting in a mixture of products, one having the same configuration and other having inverted configuration. (ii) Bromochlorodifluoromethane is a haloalkane with the chemical formula CF 2 ClBr . It is used for fire suppression and is a chlorobromocarbon. (iii) Alkenes react in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent like tetrachloromethane. The double bond breaks, and a bromine atom becomes attached to each carbon. The bromine loses its original red-brown colour to give a colourless liquid. (iv) Alkylidene dihalides are also known as geminal halides. The term gem has derived from geminal meaning for the same position. The two similar halogen atoms are attached to the same carbon atom. (v) Zaitsev's rule (or Saytzeff's rule, Saytzev's rule) is an empirical rule for predicting the favoured alkene product in elimination reactions. More generally, Saytzeff's rule predicts that in an elimination reaction, the most substituted product will be the most stable, and therefore the most favoured. Column I Column II (i) S N 1 reaction (c) Racemisation (ii) Chemicals in fire extinguisher (e) Chlorobromocarbons (iii) Bromination of alkenes (a) vic-dibromides (iv) Alkylidene halides (b) gem-dihalides (v) Elimination of HX from alkyl halide (d) Saytzeff rule

E M B I B E

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Short Answer Type>Q 75

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12th CBSE

IMPORTANT

Earn 100

Predict the major product formed when $HCl$ is added to isobutylene. Explain the mechanism involved.

Important Questions on Haloalkanes and Haloarenes

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Short Answer Type>Q 77

How can you obtain iodoethane from ethanol when no other iodine containing reagent except $NaI$ is available in the laboratory?

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Short Answer Type>Q 78

Cyanide ion acts as an ambident nucleophile. From which end it acts as a stronger nucleophile in aqueous medium? Give reason for your answer.

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Matching Type>Q 80

Match the items of Column I and Column II.

Column I	Column II
(i) $S_{N} 1$ reaction	(a) vic-dibromides
(ii) Chemicals in fire extinguisher	(b) gem-dihalides
(iii) Bromination of alkenes	(c) Racemisation
(iv) Alkylidene halides	(d) Saytzeff rule
(v) Elimination of $HX$ from alkyl halide	(e) Chlorobromocarbons

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Matching Type>Q 82

Match the reactions given in Column I with the types of reactions given in Column II.

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IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Matching Type>Q 83

Match the structures given in Column I with the names in Column II.

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Matching Type>Q 84

Match the reactions given in Column I with the names given in Column II.

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Long Answer Type>Q 95

Some alkyl halides undergo substitution whereas some undergo elimination reaction on treatment with bases. Discuss the structural features of alkyl halides with the help of examples that are responsible for this difference.

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12th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 12>Chapter 10 - Haloalkanes and Haloarenes>Long Answer Type>Q 97

Why are aryl halides less reactive towards nucleophilic substitution reactions than alkyl halides? How can we enhance the reactivity of aryl halides?