When a mixture of methane and oxygen is passed through heated molybdenum oxide,the main product formed is

Least hindered rotation about carbon-carbon bond is observed in

The reaction of propane with bromine in the presence of $UV$ light predominantly forms

In alkane compounds, the $C - H$ bond length and $H - C - H$ bond angle are respectively:

$n$-Butane on monochlorination under photochemical conditions gives an optically active compound "$P$". "$P$" on further chlorination gives dichloro compounds. The number of dichloro compounds obtained (ignore stereoisomers) is:

Among the given pairs,in which pair does the first compound have a higher boiling point than the second?