Which of the following is oxidised by $KMnO_4$?

Identify the type of reaction shown in the following chemical equation:
$C_6H_5CH_3 + Br_2 \xrightarrow{h\nu} C_6H_5CH_2Br + HBr$

Why are alkanes used as fuels?

Presence of which reagent will affect the reversibility of the following reaction,and change it to an irreversible reaction:
$CH_4 + I_2 \xrightarrow{hv} CH_3-I + HI$

Briefly explain the trends in boiling point and melting point in the alkane series.

Total number of isomeric compounds (including stereoisomers) formed by monochlorination of $2$-methylbutane is................