$C_3H_8 + Cl_2 \xrightarrow{\text{Light}} C_3H_7Cl + HCl$ is an example of which of the following types of reactions?

For the molecule $CH_3(a)-CH_2(b)-CH_2(c)-CH_2(d)-F$,arrange the hydrogens $a, b, c, d$ in decreasing order of their reactivities towards free radical chlorination.

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

Assertion $(A)$: Cyclohexane is the most stable cycloalkane.
Reason $(R)$: Cyclopropane and cyclobutane are less stable due to angle strain and torsional strain.
The correct answer is

How many isomeric vicinal-dihalides are possible for the compound having molecular formula $C_3H_6Cl_2$?