3. How do you convert:
(i) Chlorobenzene to biphenyl
(ii) (ii) Propene to l-iodopropane
(iii) 2-bromobutane to but-2-ene
4. Give reasons for the following:
(i) Ethyl iodide 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.
5. Answer the following questions:
(i) What is meant by chirality of a compound? Give an example.
(ii) Which one of the following compounds is more easily hydrolyzed by KOH and
why?
Answers
Answer:
For Q3 I have attached the equations . Do check
Q4]
(i) Iodide is a better leaving group because of its larger size than bromide, therefore, ethyl iodide undergoes SN 2 reaction faster than ethyl bromide.
(ii) (±) 2-butanol is a racemic mixture. It is a mixture which contains two enantiomers in equal proportion and thus, have zero optical rotation due to internal compensation. Therefore, it is optically inactive
(iii) In halobenzenes (like chlorobenzene), the lone pair of electrons on halogen atom is delocalised on the benzene ring. As a result, C — X bond (C — Cl bond in case of chlorobenzene) acquires some double bond character while in $CH _{ 3 }$— X, C—X bond is a pure single bond. Therefore, C—X bond in halobenzene is shorter than in $CH _{ 3 }$—X
Q5]
1) The molecules or ions that cannot be superimposed are called chiral. Chirality is the property exhibited by such molecules. A chiral molecule and its non-superimposable mirror image are special types of stereoisomers called enantiomers.
For example: 2-butanol (butane with an -OH substituent on the second carbon) and its mirror image are non-superimposable
Part 2 of Q5 is incomplete
Answer:
1 ... Chlorobenzene to biphenyl
