Question

Consider the following reaction and statements:

\[\ce{[Co(NH3)4Br2]^+ + Br^- -> [Co(NH3)3Br3] + NH3}\]

1. Two isomers are produced if the reactant complex ion is a cis-isomer.
2. Two isomers are produced if the reactant complex ion is a trans-isomer.
3. Only one isomer is produced if the reactant complex ion is a trans-isomer.
4. Only one isomer is produced if the reactant complex ions is a cis-isomer.

The correct statements are:

Options

• (I) and (II)

• (I) and (III)

• (III) and (IV)

• (II) and (IV)

Answer 1

(I) and (III)

Explanation:

• Starting from cis-[Co(NH₃)₄Br₂]⁺, replacing one NH₃ by Br⁻ can give both fac- and mer-[Co(NH₃)₃Br₃] (two isomers).
  
• Starting from trans-[Co(NH₃)₄Br₂]⁺, the product must contain a trans Br–Br pair, so only the mer form is possible (one isomer).