How many isomeric vicinal-dihalides are possible for the compound having molecular formula $C_3H_6Cl_2$?

Find the number of monochlorinated products formed by $2$-methylbutane. $(\text{Only structural isomers})$

The boiling points of three saturated hydrocarbons $A, B$ and $C$ are $-102\,^{\circ}C, -43.44\,^{\circ}C$ and $-0.6\,^{\circ}C$ respectively. The hydrocarbon containing the highest number of carbon atoms is .......

$A$ certain alkane is mixed with chlorine and irradiated with ultraviolet light. It yields only one monochloroalkane. Which alkane is it?

Choose the chain terminating step.
$(1)$ $H_2 \to H^{\bullet} + H^{\bullet}$
$(2)$ $Br_2 \to Br^{\bullet} + Br^{\bullet}$
$(3)$ $Br^{\bullet} + HBr \to H^{\bullet} + Br_2$
$(4)$ $H^{\bullet} + Br_2 \to HBr + Br^{\bullet}$
$(5)$ $Br^{\bullet} + Br^{\bullet} \to Br_2$

The correct order of boiling points of the following molecules is:
$(i)$ $n$-Hexane
$(ii)$ $2$-methylpentane
$(iii)$ $2,3$-dimethylbutane