Chemistry - STEREO ISOMERISM Question with Solution | TestHub
Identify the following structures as achiral or chiral:
(a) 
(b) 
(c) 
(d) 
(e) 
(f) 
(g) 
(h) 
(i) 
(j) 
Options:
Answer:
Solution:
Achiral structures : (a) CH2Cl2 - no stereocentre, several planes of symmetry. (b) meso-2,3-dibromobutane - the (2R,3S) form shown has an internal plane of symmetry. (c) cis-1,2-dimethylcyclobutane - internal mirror plane through C3 and the C1-C2 midpoint. (d) trans-1,3-dibromocyclobutane - plane of symmetry through C1 and C3. (e) 1,1-dichloroethane - no stereocentre. (f) Ethylene - planar, several planes and a centre of symmetry.
Chiral structures : (g) butan-2-ol - one stereocentre, no symmetry element. (h) 1,2-dichloropropane - one stereocentre. (i) trans-1,2-dimethylcyclobutane - two stereocentres, no plane or centre of symmetry. (j) (2R,3R)-2,3-dibromobutane - no internal plane; its mirror image (2S,3S) is nonsuperimposable.
Ans. Achiral : (a)-(f) ; chiral : (g)-(j).
