Cetane is a compound which has very good ignition property. Chemically it is

$2, 3-$dimethylhexane contains tertiary,secondary,and primary carbon atoms,respectively:

$A$ sample of $2,3-$dibromo$-3-$methylpentane is heated with zinc dust. The resulting product is isolated and then heated with $HI$ in the presence of red phosphorus. Indicate the structure that represents the final organic product formed in the reaction.

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.

Describe the Kolbe electrolysis reaction of $C_{2}H_{5}COO^{-}Na^{+}$ at the anode and cathode.

If the octane number of a sample of petrol is $40$,it is a mixture of........and............