Chemistry - STEREO ISOMERISM Question with Solution | TestHub
Match the following :
Column-I | Column-II |
|---|---|
(A) | (P) C2-axis of symmetry is present |
(B) | (Q) C3-axis of symmetry is present |
(C) | (R) Plane of symmetry is present |
(D) | (S) Center of symmetry is present |
| (T) S4 alternative axis of symmetry |
Options:
Answer:
Solution:
Ans. A P, R, S; B P, Q, R, S; C P, R; D P.
Sol. A (trans-1,2-dichloroethene, C2h): C2 axis perpendicular to the plane, mirror planes (molecular plane etc.) and a centre of symmetry at the midpoint of C=C : P, R, S.
B (coronene, D6h): has C6 (hence C2 and C3) axes perpendicular to the plane, mirror planes and a centre of symmetry : P, Q, R, S.
C (cis-but-2-ene, C2v): a C2 axis (through the midpoint of C=C, in the molecular plane) and two mirror planes, but no centre of symmetry : P, R.
D (meso-tartaric acid, Fischer projection): a C2 axis in the plane of the paper passing through the midpoint of the C2-C3 bond maps the upper half onto the lower half (CO2H into CO2H, OH into OH, H into H). As drawn (eclipsed Fischer) there is no mirror plane, no centre and no S4 : P only.
