What is the number of structural isomers of monohalogenated $\mathrm{n}$-butane?

Which of the following does not exhibit position as well as chain isomerism?

(i) ${\mathrm{C}}_2{\mathrm{H}}_3\mathrm{Br}$  (ii) ${\mathrm{C}}_4{\mathrm{H}}_9\mathrm{Br}$

What effect should the following resonance of vinyl chloride have on its dipole moment?

Arrange the following in the order of their increasing reactivity in nucleophilic substitution reactions.

${\mathrm{CH}}_3\mathrm{F}, {\mathrm{CH}}_3\mathrm{Cl},{\mathrm{CH}}_3\mathrm{Br}, {\mathrm{CH}}_3\mathrm{I}$

Identify $\mathrm{A}$ and $\mathrm{B}$ in the following :

${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{Br}\stackrel{\mathrm{alc}. \mathrm{KOH}}{⟶}\mathrm{A}\stackrel{\mathrm{HBr}}{⟶}\mathrm{B}$

Identify $\mathrm{A}$ and $\mathrm{B}$ in the following :

${\mathrm{CH}}_3\mathrm{Br}+\mathrm{Mg}$ (ether) $⟶\mathrm{A}\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}\mathrm{B}$