The secondary valency of Co in the complex \([Co(NH_3)_5(NO_2)]^{2+}\) is
Show Hint
- 5
- 1
- 4
- 6
The Correct Option is D
Solution and Explanation
In Werner's theory, the secondary valency of the central metal is its coordination number, that is the number of ligand atoms directly attached (coordinated) to the metal.
Step 1:
Count the ligands joined to Co in \([Co(NH_3)_5(NO_2)]^{2+}\). There are five \(NH_3\) molecules, each donating one pair of electrons, and one \(NO_2\) group, also attached at one point.
Step 2:
Total ligand attachments = 5 + 1 = 6. So the coordination number, which is the secondary valency, is 6.
Answer: Option (D) — the secondary valency of Co is 6.
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