Chemistry - STEREO ISOMERISM Question with Solution | TestHub

Explain Question: Asking abut the number of POS in ${\mathrm{CH}}_4$ and ${\mathrm{CH}}_3\mathrm{Cl}$.

Concept: This question is based on plane of symmetry (POS).

Solution:

A Plane of symmetry (also called a mirror plane) is an imaginary plane that divides a molecule or object

into two halves that are mirror image of each other.

(a) In ${\mathrm{CH}}_4$ each plane containing the carbon atom and two hydrogen atoms is a POS. There are six planes in ${\mathrm{CH}}_4(\mathrm{x}=6)$

(b) In ${\mathrm{CH}}_3\mathrm{Cl}$ each plane containing the carbon atom Cl - atom and one hydrogen atom is a POS . There are three planes in ${\mathrm{CH}}_3\mathrm{Cl}(\mathrm{y}=3)$

Total x + y = 6 + 3 + = 9

Final answer: 9