Assertion and reason

Exercise and reference answers

Questions

1. Reason

   Ethane-1,2-diamine is didentate, so each ligand supplies two donor atoms.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   [Co(en)₃]³⁺ has coordination number 6 despite holding three ligands.

2. Reason

   A chelate ligand grips the metal through several donor atoms at once.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Chelate complexes are unusually stable.

3. Reason

   A ligand may form a pi bond with the central metal.

   Verdict

   The assertion is false and the reason is true.

   Assertion

   Coordination number counts pi bonds as well as sigma bonds.

4. Reason

   They accept electron pairs from the ligands.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Central metal atoms in complexes act as Lewis acids.

Explanation