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) Ci (Center of symmetry) is present |
(D) | (S) Plane of symmetry is present |
Options:
Answer:
Solution:
Ans. A P, R, S; B Q, S; C P, Q, R, S; D P, R, S.
Sol. A (1,4-dibromo-2,5-dichlorobenzene): has C2 axes, a centre of symmetry (the ring centre, Br mapping onto Br and Cl onto Cl) and mirror planes (the molecular plane and planes perpendicular to it) : P, R, S.
B (benzene-1,3,5-triol): the three OH groups at 1, 3, 5 give a C3 axis through the ring centre, plus mirror planes; there is no C2 axis and no centre of symmetry : Q, S.
C (staggered ethane, D3d): has a C3 axis along C-C, three C2 axes perpendicular to it, a centre of symmetry midway of C-C, and three diagonal mirror planes : P, Q, R, S.
D (trans-but-2-ene, C2h): has a C2 axis perpendicular to the molecular plane, a centre of symmetry at the midpoint of C=C, and mirror planes (the molecular plane and the plane perpendicular to it through the C2 axis) : P, R, S.
