Chemistry - STEREO ISOMERISM Question with Solution | TestHub
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Options:
Answer:
Solution:
13. Yes : the C=N bond of the oxime carries two different groups on carbon (H, Br) and the N-OH is stereogenic.
14. No : the oxygen of C=O carries only one substituent, so E/Z isomerism about C=O does not arise.
15. Yes : the C=N bond of the iminium ion carries two different groups on N (CH₃, H) and on C (H, CH₃).
16. No : the allene C=C=C unit gives axial (optical) isomerism, not geometrical isomerism.
17. Yes : the cumulene C=C=C=C unit has an odd number of double bonds, so its terminal groups are coplanar and E/Z isomerism exists.
18. Yes : cis-trans isomerism of the two CH₃ groups about the cyclobutene ring.
19. No : one terminal carbon of the cumulene is =CH₂ (two identical H atoms).
20. No : each double-bond carbon belongs to an unsubstituted cyclobutane ring, so its two ring paths are identical.
21. Yes : the two bridgehead CH₃ groups can be cis or trans to each other.
22. Yes : cis-trans isomerism of 1,2-dimethylcyclohexane.
23. Yes : each double-bond carbon carries two different atoms (Cl, F on one; Br, I on the other).
24. No : the C≡C triple bond is linear, so geometrical isomerism is impossible.
