The main component of marsh gas is ......... .

An alkane (molecular weight $72$) forms only one monochlorinated product. Its formula is

Assertion $(A)$: Cyclohexane is the most stable cycloalkane.
Reason $(R)$: Cyclopropane and cyclobutane are less stable due to angle strain and torsional strain.
The correct answer is

Which compound in the following will give only one mono-chlorination product in the presence of light?

Methane reacts with steam at $1273 \ K$ in the presence of a nickel catalyst to form:

$2-$Methylbutane on reacting with bromine in the presence of sunlight gives mainly: