NEETChemistryCoordination Compounds
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): [Co(NH₃)₅(SO₄)]Br and [Co(NH₃)₅Br]SO₄ are ionisation isomers and the coordination number of cobalt in both complexes is 6. Reason (R): Ionisation isomerism occurs when the counter ion in a complex salt is itself a potential ligand and can displace a ligand which can then become the counter ion. In
Options
- ABoth Assertion (A) and Reason (R) are true but Reason (R) is NOT the correct explanation of Assertion (A).
- BAssertion (A) is true but Reason (R) is false.
- CAssertion (A) is false but Reason (R) is true.
- DBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Correct answer
D. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Step-by-step solution
Assertion (A) is true: The complexes [Co(NH₃)₅(SO₄)]Br and [Co(NH₃)₅Br]SO₄ yield different ions in solution ( Br^- and SO₄²⁻ respectively), hence they are ionisation isomers. In both complexes, the central cobalt ion is bonded to 6 donor atoms (5 from NH₃ and 1 from SO₄²⁻ or Br^- ), making the coordination number 6. Reason (R) is true: This is the exact definition of ionisation isomerism as per NCERT. The counter ion ( Br^- or SO₄²⁻ ) acts as a potential ligand and displaces a ligand from the coordination sphere. R