Chemistry - STEREO ISOMERISM Question with Solution | TestHub
What makes molecule chiral ? Give three examples of different types of chirality. State with explanations whether the following compounds are chiral.
(1) 
(2) 
(3) CH2Cl2 (4) 
(5) SOCl2 (6) 
Options:
Answer:
Solution:
Ans. (1), (2) and (6) are chiral; (3), (4) and (5) are not chiral.
Sol. Molecules are chiral if they have no plane, centre or alternating axis of symmetry. This may arise from a tetrahedral atom with four different substituents (centre of chirality), from a cumulated double-bond system (axis of chirality), or from a molecule forced into a shape lacking these elements.
(1) Bromochlorofluoromethane: a tetrahedral carbon with four different groups : CHIRAL (centre of chirality). (2) CHF=C=CHCH3: each terminal sp2 carbon bears two different groups : axially CHIRAL (axis of chirality). (3) CH2Cl2: two identical H atoms; has planes of symmetry : NOT chiral. (4) cis-1,2-Dichlorocyclopropane: meso, internal plane : NOT chiral. (5) SOCl2: pyramidal, but the two identical Cl atoms leave a plane of symmetry : NOT chiral. (6) trans-1,2-Dichlorocyclopropane: no symmetry element : CHIRAL.
