$CH_4$ is formed when:

Different hydrogen atoms in the compound are represented by alphabets:
$CH_3(A)-CH=CH(B)-CH_2(C)-CH_2(D)-CH(E)(CH_3)_2(F)$
Arrange them in decreasing order of reactivity towards free radical substitution.

Complete the following combustion reactions:
$1$. Complete oxidation of methane
$2$. Complete oxidation of butane

Identify the major product of the following reaction: $CH_3-CH(CH_3)-CH_2-COOH \xrightarrow{NaOH + CaO, \Delta}$

Which of the following is obtained as the major product when an excess of methane is treated with a limited amount of chlorine in the presence of $UV$ light?

The addition of tetraethyl lead to petrol: