The main constituent of marsh gas is:

Among the following free radical bromination reactions,select those in which a $2^o$ halide is the major product. The reactions are as follows:
$(P)$ Cyclohexane + $Br_2/hv$
$(Q)$ Methylcyclobutane + $Br_2/hv$
$(R)$ Ethylbenzene + $Br_2/hv$
$(S)$ $3-$Methylhexane + $Br_2/hv$
$(T)$ Decalin + $Br_2/hv$
$(U)$ Butane + $Br_2/hv$

Identify the major product of the following reaction: $CH_3-CH(CH_3)-CH_2-COOH \xrightarrow{NaOH + CaO, \Delta}$

Give the mechanism of chlorination of methane.

$5 \, L$ 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

Identify $D$ and $E$ in the following reaction: $CH_3-CH(CH_3)-CH(CH_3)-CH_3 \xleftarrow[ether]{Na} R'-Br$ $\xrightarrow{Mg} D$ $\xrightarrow{H_2O} E$