Write down the structure and IUPAC name for neo-pentylbromide.
The structure of neo-pentylbromide is
IUPAC name $\Rightarrow$ I-bromo -2,2-dimethylpropane
Common name $\Rightarrow$ neo-pentylbromide
A hydrocarbon of molecular mass $72 \mathrm{~g} \mathrm{~mol}^{-1}$ gives a single monochloro derivative and two dichloro derivatives on photo chlorination. Give the structure of the hydrocarbon.
Since, the molar mass of hydrocarbon is $72 \mathrm{~g} \mathrm{~mol}^{-1}$ thats why the hydrocarbon is $\mathrm{C}_5 \mathrm{H}_{12}$ i.e., pentane.
On photo chlorination, it gives monochloro derivatives so, all the hydrogen atoms must be equivalent and the structure of the compound will be
Name of the alkene which will yield/chloro 1-methylcyclohexane by its reaction with HCl . Write the reactions involved.
Two alkenes are possible
Addition takes place in accordance with Markownikoff's rule i.e., negative part of the adding molecule will get attached to that carbon which has lesser number of hydrogen atom.
Which of the following haloalkanes reacts with aqueous KOH most easily? Explain giving reason.
(i) 1-bromobutane
(ii) 2-bromobutane
(iii) 2-bromo-2-methylpropane
(iv) 2-chlorobutane
2-bromo-2-methylpropane (iii), is a tertiary alkyl halide and it will form a stable carbocation on ionisation.
1-bromobutane is primary alkyl halide whereas 2-bromobutane and 2-chlorobutane is secondary alkyl halide.
Why can aryl halides not be prepared by reaction of phenol with HCl in the presence of $\mathrm{ZnCl}_2$ ?
Due to resonance in phenol, $\mathrm{C}-\mathrm{O}$ bond of phenol has some partial double bond character. Partial double bond character strengthen the bond. So, It is difficult to break this $\mathrm{C}-\mathrm{O}$ bond of phenol while the $\mathrm{C}-\mathrm{O}$ bond of alcohol is purely single bond and comparatively weaker bond.
So alkyl halides can be prepared by the reaction of alcohols with HCl in the presence of $\mathrm{ZnCl}_2$ while aryl halides can not be prepared by reaction of phenol with HCl in the presence of $\mathrm{ZnCl}_2$.
