Which of the following compounds has substituents that are cis to each other? (i) $\mathrm{CH}=\mathrm{CH}\mathrm{Br}\mathrm{Cl}$ (ii) $\mathrm{CH}=\mathrm{CH}\mathrm{Br}\mathrm{Br}$ (iii) $\mathrm{CH}=\mathrm{CH}\mathrm{Cl}\mathrm{Br}$ (iv) $\mathrm{CH}=\mathrm{CH}\mathrm{Cl}\mathrm{Cl}$

• A. iii and iv
• B. ii and iv
• C. i and iii
• D. i and ii

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of cis and trans isomers in alkenes. Cis isomers have substituents on the same side of the double bond, while trans isomers have substituents on opposite sides.
2. Step 2: For each compound, identify the substituents attached to the carbons of the double bond and determine their relative positions (same side or opposite side).
3. Step 3: Draw or visualize the structure of each alkene with its substituents to clearly see if the substituents are on the same side (cis) or opposite sides (trans).
4. Step 4: Analyze compound (ii) with two bromine substituents and compound (iv) with two chlorine substituents. Since the substituents are identical on each carbon, check if they can be arranged on the same side (cis).
5. Step 5: Conclude which compounds have substituents cis to each other based on your analysis, focusing on the symmetry and substituent identity to distinguish cis from trans isomers.