The number of different substitution products possible when bromine and ethane are allowed to react is:

Tetraethyl lead $(TEL)$ is used as a ............... .

The statement "Alkane compounds normally resist oxidation" means what?

Given below are two statements:
Statement $I$: Methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of sodium acetate and reaction of $CH_3MgBr$ with water.
Statement $II$: Methane cannot be prepared from unsaturated hydrocarbons and by Wurtz reaction.
In the light of the above statements, choose the correct answer from the options given below.

When a mixture of methane and oxygen is passed over heated molybdenum oxide, the product obtained is ........ .

Compound $A$ on reaction with chlorine in the presence of $U.V.$ light gives $B$; which when reacted with $NaNO_{2}$ in the solvent $N, N$-dimethylformamide $(DMF)$,gives $2$-nitrobutane. The compound $A$ is: