question_answer 11)

Which of the following compounds willshow cis-trans isomerism? (i) \[{{(C{{H}_{3}})}_{2}}C=CH-{{C}_{2}}{{H}_{5}}\] (ii) \[{{H}_{2}}C=C\,B{{r}_{2}}\] (iii) \[{{C}_{6}}{{H}_{5}}CH=CH-C{{H}_{3}}\] (iv) \[C{{H}_{3}}CH=CClC{{H}_{3}}\]  

Answer:

Alkenes (iii) and (iv) have different atoms or groups on each carbon atom of the double bond and hence show cis-trans isomerism but alkenes (i) and (ii) do not show geometrical isomerism because two identical groups are attached to one of the doubly bonded carbon atoms.