PANDEY’S TUTORIALS

CLASS – 12TH F.M. –

SUBJECT – CHEMISTRY TIME –

TOPIC – HALOALKANES AND HALOARENES ASSIGNMENT

SECTION A (1 MARKS)

 Write a IUPAC name of

 Give the IUPAC name of the following compound :

 Write the structure of the compound :-

4-tert-butyl-3-iodoheptane.

 Identify the products A and B formed in the following reaction.

CH3 – CH2 – CH = CH – CH3 + HCL → A + B

 Write the structure and names of the compound formed, when compound A with molecular formula C7H8, is treated with Cl2 in the presence of FeCl3.

 Out of o- and p – dibromobenzene, which one has higher melting point and why?

 How methyl bromide be preferentially converted to methyl isocyanide?

 Write the structure of an isomer of compound C4H9Br, which is most reactive towards SN1 reaction?

Which one is more reactive towards SN1 reaction and why?

 Which would undergo SN2 reaction faster in the following pair and why?

 Chloroform is stored in closed dark coloured bottles completely filled, so that air is kept out. Explain.

 Iodoform has antiseptic properties. Give one reason to support it.

SECTION B (2 MARKS)

 Give the IUPAC names of the following compounds.

(i) CH3CH(Cl)CH(Br)CH3

(ii) CHF2CBrClf

(iii) ClCH2C CCH2Br

(iv) CH3C(p – ClC6H4)2CH(Br)CH6

 Write the structure of the following organic halogen compounds.

(i) 1-bromo-4 sec-butyl-2-methylbenzene

(ii) 1, 4-dibromobut-2-ene

 Draw the structure of major monohalo products in each of the following reactions.

 Write the structure of the major organic products in each of the following reactions.

(i) CH3CH2CH2Cl + NaI Acetone/Heat→

(ii) CH3CH2CH2OH + SOCl2 Pyridine/ →

(iii) CH3CH2CH = CH2 + HBr Peroxide/ →

(iv) CH3CH = C(CH3) + HBr ( )/ →

                     CH3

 Why aryl halides cannot be prepared by the reaction of phenol with HCl in the presence of ZnCl2?

 Arrange each set of compounds in the order if increasing boiling point.

(i) Bromomethane, bromoform, chloromethane, dibromomethane

(ii) 1-chloropropane, iso-propyl chloride, 1-chlorobutane

 (i) Which alkyl halide from the following pair is chiral and undergoes faster towards SN2 reaction?

(ii) Out of SN1 and SN2, which reaction occurs with:-

      (a) Inversion of condifuration?

      (b) Racemisation?

 Tert-butylbromide reacts with aq. NaOH by SN1 mechanism while n-butylbromide reacts by SN2 mechanism. Why?

 Write the structure of the major organic product in each of the following reactions:

(i) (CH3)3CBr + KOH Ethanol/Heat→

(ii) CH3CH(Br)CH2CH3 + NaOH Water/ →

(iii) CH3CH2Br + KCN (aq.ethanol)/ →

(iv) C6H5ONa + C2H5Cl ( )/ →

 Bring out the following conversations.

(i) Chlorobenzene to 2-chloroacetophenone

(ii) Chloroethane to butane

 Aryl halides are extremely less reactive towards nucleophilic substitution. Predict and explain the order of reactivity of the following compounds towards nucleophilic substitution.

SECTION C (3 MARKS)

 Draw the structures of major monohalo products in each of the following reactions.

 Explain.

(i) Why the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride?

(ii) Why alkyl halides, though polar, are immiscrible with water?

 Following compounds are given to you :-

2-bromopentane, 2-bromo-2-methylbutane, 1-bromopentane

(i) Write the compound which is most reactive towards SN2 reaction.

(ii) Write the compound which is optically active.

(iii) Write the compound which is most reactive towards β-elimination reaction.

 (i) Account for the following :-

(a) Electrophilic substitution reactions in haloarenes occur slowly.

(b) Haloalkanes, though polar, are insoluble in water.

(ii) Arrange the following compounds in increasing order of reactivity towards SN2

2-bromo-2-methylbutane, 1-bromopentane, 2-bromopentane.

 What happens when :-

(i) Chlorobenzene is treated with Cl2/FeCl3?

(ii) Ethyl chloride is treated with AgNO2?

(iii) 2-bromopentane is treated with alcoholic KOH?

 (i) Write the structural formula of A, B, C and D in the following sequence of reaction.

(ii) Illustrate Sandmeyer’s reaction with help of a suitable example.

 Give reasons for the followings.

(i) Ethyl iodine undergoes SN2 reaction faster than ethyl bromide.

(ii) (±) 2-butanol is optically inactive.

(iii) C – X bond length in halobenzene is smaller than C – X bond length in CH3 – X.

 Give reasons :-

(i) n-butyl bromide has higher boiling point than t-butyl bromide.

(ii) Racemic mixture is optically inactive.

(iii) The presence of nitro group ( - NO2) at o/p positions, increases the reactivity of haloarenes towards nucleophilic substitution reactions.

SECTION D (5 MARKS)

 How can the following conversions be carried out?

(i) 2-bromppropane to 1-bromopropane

(ii) But-1-ene to n-butyl iodide

(iii) 2-chloropropane to 1-propanol

(iv) iso-propyl alcohol to iodoform

(v) Chlorobenzene to p-nitrophenol