Which reactions are difficult for alkanes?

The major product of which of the following reactions will not decolorize $Br_2 + H_2O$?

The general formula of a cycloalkane is

Give the decreasing order of reactivity for the halogenation reaction of alkanes.

Dry distillation of sodium propanoate with sodalime gives

$5 \, L$ of an alkane requires $25 \, L$ of oxygen for its complete combustion. If all volumes are measured at constant temperature and pressure,the alkane is