Problem 12
Explain why (i) the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride? (ii) alkyl halides, though polar, are immiscible with water? (iii) Grignard reagents should be prepared under anhydrous conditions?
Problem 13
Give the uses of freon 12, DDT, carbon tetrachloride and iodoform.
Problem 14
Write the structure of the major organic product in each of the following reactions: (i) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Cl}+\mathrm{NaI} \frac{\text { acetone }}{\text { heat }}\) (ii) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CBr}+\mathrm{KOH} \frac{\text { ethanol }}{\text { heat }}\) (iii) \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{2} \mathrm{CH}_{3}+\mathrm{NaOH} \stackrel{\text { water }}{\longrightarrow}\) (iv) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Br}+\mathrm{KCN} \stackrel{\text { aq. ethanol }}{\longrightarrow}\) (v) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{ONa}+\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl} \longrightarrow\) (vi) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{SOCl}_{2} \longrightarrow\) (vii) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CH}_{2}+\mathrm{HBr} \stackrel{\text { peroxide }}{\longrightarrow}\) viii) \(\mathrm{CH}_{8} \mathrm{CH}=\mathrm{C}\left(\mathrm{CH}_{2}\right)_{2}+\mathrm{HBr}\)
Problem 16
Arrange the compounds of each set in order of reactivity towards \(\mathrm{S}_{N} 2\) displacement: (i) 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane (ii) 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 2-Bromo-3-methylbutane
Problem 17
Out of \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{Cl}\) and \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHClC}_{6} \mathrm{H}_{5}\), which is more easily hydrolysed by aqueous KOH.
Problem 20
The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain.
Problem 21
Primary alkyl halide \(\mathrm{C}_{4} \mathrm{H}_{9} \mathrm{Br}\) (a) reacted with alcoholic KOH to give compound (b). Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), \(\mathrm{C}_{8} \mathrm{H}_{18}\) which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.
Problem 22
What happens when (i) n-butyl chloride is treated with alcoholic KOH. (ii) bromobenzene is treated with Mg in the presence of dry ether, (iii) chlorobenzene is subjected to hydrolysis, (iv) ethyl chloride is treated with aqueous \(\mathrm{KOH}\), (v) methyl bromide is treated with sodium in the presence of dry ether, (vi) methyl chloride is treated with KCN?
