Read the passage carefully and answer the Questions.

Haloalkanes undergo nucelophilic substitution reactions owing to the polarity of C-X bond. The nucleophile reacts with the haloalkane on the carbon possessing a partial positive charge holding the halogen atom. The halogen atom X is replaced by a nucleophile. Depending on the kinetics and mode of bond breaking, the mechanism can be either $S_N1$ or $S_N2$ reaction. The rate of $S_N1$ reaction is governed by the stability of carbocation and in $S_N2$ reaction, the rate of reaction is governed by steric factor. Chirality is the main factor in both $S_N1$ and $S_N2$. In $S_N1$ reaction, the chirality of alkyl halide is accompanied by racemization of the product, while in $S_N2$ reaction, the product is characterized by inversion of configuration. The structure of alkyl halide and the nature of the solvent also governs the mechanism of the substitution.

What is chiral carbon?

Attached to four different atoms or groups

The correct answer is Option (2) → Attached to four different atoms or groups

A chiral carbon is defined as:

A carbon atom attached to four different atoms or groups

Such a carbon shows optical activity and gives non-superimposable mirror images (enantiomers).