Which compound produces $CH_4$ when treated with water?

$A$ compound reacts with $Cl_2$ to give product $(B)$,and the reaction of product $(B)$ with $(Zn + \text{dilute } HCl)$ gives back the original substance $(A)$. Give the structures of $(A)$ and $(B)$.

How many isomers of monobromo derivatives are obtained on the bromination of the following compound?

Which of the following is $NOT$ obtained when a mixture of methyl bromide and ethyl bromide is treated with sodium metal in the presence of dry ether?

The reaction of $1, 3-$dibromopropane with metallic zinc gives ..........

Complete the following reactions:
$(i)$ $n$-heptane $\xrightarrow[773 \ K, 10-20 \ atm]{Cr_2O_3/V_2O_5/Mo_2O_3}$ ?
(ii) $CH_4 + O_2 \xrightarrow[523 \ K, 100 \ atm]{Cu}$ ?