Chemistry - STEREO ISOMERISM Question with Solution | TestHub
Amongst the given option, the compound(s) in which all the atoms are in one plane in all the possible conformations (if any), is (are) -
Options:(select one or more)
Answer:
Solution:
Question Explanation:
The question asks which of the given compounds remain completely planar in all their possible
conformations, if such conformations exist.
Concept: This question is based on Conformers, planarity, hybridization.
Solution :
Planarity depends on hybridization and rotational freedom around bonds.
Compound 1: 2,3-dimethylbuta-1,3-diene
It has a single bond between two sp2 carbons (C₂–C₃), allowing rotation. Due to this, it can adopt s-cis and s-trans conformations, and not all conformations are planar.
Compound 2: But-1-en-3-yne
It contains sp2 carbons (C=C) and sp carbons (C≡C). The triple bond enforces linearity and the double bond restricts rotation, so all atoms remain in one plane.
Compound 3: Ketene (H2C=C=O)
The central carbon is sp-hybridized, making the molecule linear and planar. All atoms lie in a single
plane. Compound 4: Allene (H2C=C=CH2 )
Due to cumulative double bonds, the two terminal CH2 groups lie in mutually perpendicular planes, so the molecule is non-planar .
