Question

Assertion : Co(IV) is known but Ni(IV) is not.
Reason : Ni(IV) has $d^4$ electronic configuration.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

Both Co and Ni have (IV) oxidation state. Ni (IV) has $3d_6$ electronic configuration.

Metals	Outer electronic configuration	Oxi. states
Co	3d74s2	+2, +3, +4
Ni	3d84s2	+2, +3, +4