Explain why thionyl chloride method is preferred for preparing alkyl chlorides from alcols?

1

(a)

Because the products of the reaction . i.e., SO₂ and HCI being gases escape into the atmosphere leaving behind alkyl chorides in almost pure state. 

How will you obtain 1-bropropane from propane ?

1

(a)

With HBr in presence of perxides (CH₃ CH = CH₂ \(\xrightarrow { HBr.peroxides } \) CH₃CH₂CH₂Br)

How will you bring about the conversion : methyl bromide to methyl iodide ?

1

(a)

CH₃ __ Br  + Nal \(\xrightarrow [ (Filkenstein\ reaction) ]{ Dry\ acetone } \) CH3 __I
                     Methyl bromide                               Methyl iodide

Organic halogon compounds used in industry as solvents are chlorides rather than bromides and iodides. Explain

1

(a)

Organic alkyl chlorides are widely used as solvents in industry because chlorides are not only more stable but are also more volatile than bromides and iodides.

Which is a better nucleophile, a bromide ion or an idodide ion ?

1

(a)

Because of bigger size and lower electronegativity, iodide ion can donate a pair of electrons more easily than bromide ion and hence iodide ion is a better nucleophile than bromide ion.