What is the molar mass of the third homologue of the alkane series?

$(A) + Cl_2 \xrightarrow{hv} \text{monochloro product}$. To maximize the yield of the monochloro product in the above reaction:

Consider the isomers of the hydrocarbon with molecular formula $C_5H_{10}$. These isomers do not decolourise $KMnO_4$ solution. These isomers are subjected to chlorination with chlorine in the presence of light to give monochloro compounds. The total number of monochloro compounds (structural isomers only) formed from all these isomers is . . . . . . .

Which of the following yields both alkane and alkene?

How many monobrominated product$(s)$ (including stereoisomers) would form in the free radical bromination of $n$-butane?

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 + $Br_2/hv$