Question

What are Chiral centers and chirality?

Answer 1

Hint: Chiral objects are those whose mirror image can’t be superimposed over the original.
In case of hydrocarbons, we say that the mirror image of the $\text{s}{\text{p}}^3$ hybridized carbon atom and the substituents attached to it have no symmetry.

Complete answer: Chirality- It is the property of a hydrocarbon chain, when its mirror image is not superimposable.
-To check whether the mirror image is superimposable or not, we check for the plane of symmetry.
-Plane of symmetry is an imaginary plane that bisects the molecule, such that the resulting two halves are the identical mirror images of each other.
-If the molecule has a plane of symmetry, it is not chiral. Hence it is called achiral.
-If the molecule does not have a plane of symmetry it is said to be chiral.
-A molecule is always chiral when all the groups attached to the central carbon are different.
-Then the molecule can never have a plane of symmetry as all the groups attached are different and the mirror images could never be identical.
-Hence the molecule is said to be chiral.
-Chiral center: it is the carbon center which has all different groups attached to it in the hydrocarbon chain.
-It is often marked with ${}^{″}{\ast }^{″}$.

-In the example given above, the carbon atom has four different groups attached to it, namely Cl, H, Br, F.
-The mirror image of this molecule is non superimposable.

Note:
A chiral compound and its mirror images are enantiomers.
Enantiomers are the pair of molecules who are mirror images of each other but cannot be superimposed on each other.
These are a type of stereoisomers (isomers with different spatial arrangements.