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JAMB Chemistry 1990 Question 42

Question 42

Introduction to Organic Chemistry

The structure of cis-2-butene is (see the structures in the figure)

Diagram for this question
  1. A.CH3—CH = CH—CH3.
  2. B.Structure B: CH3 and H on each carbon of C=C, with both CH3 groups on the same side
  3. C.Structure C: CH3 and H on each carbon of C=C, with the CH3 groups on opposite sides
  4. D.Structure D: CH3 and H on one carbon of C=C, two CH3 groups on the other
Show the answer and explanation

Answer: B (Structure B: CH3 and H on each carbon of C=C, with both CH3 groups on the same side)

Explanation

In a cis isomer the two like groups are on the same side of the double bond. Structure B has both CH3 groups on the same side; C is the trans isomer.