Integer Answer Type Questions for JEE: Coordination Compounds | Chapter-wise Tests for JEE Main & Advanced PDF Download

Q.1. The number of unpaired electrons in the complex ion [CoF₆]^3- is

Ans. 4
Configuration of Co = 3d⁷4s²
Configuration of Co⁺³ = 3d⁶
Number of unpaired electron = 4

Q.2 Oxidation state of Cr in the following complex is

Ans. +3

Among the bridging ligands, O₂ is a neutral ligand and [O-O]^2- is a bidentate negative ligand. Since the net charge over the complex is 4+, each chromium atom has an oxidation state of +3.

Q.3. If excess of AgNO₃ solution is added to 100 ml of 0.024 M solution of dichlorobis(ethylene diamine)cobalt(III) chloride, how many moles of AgCl will be precipitated?

Ans. 0.0024
The formula of the complex is [CoCl₂(en)₂]Cl.
[CoCl₂(en)₂]Cl + AgNO₃ → AgCl↓ + [CoCl₂(en)₂]NO₃
Moles of complex = Moles of AgCl = 100 x 10^-3 x  0.024 = 0.0024

Q.4. The sum of coordination number and oxidation state of Cr in K₃[Cr(C₂O₄)₃] are

Ans. 9
Its coordination number will be 6 because it is bonded with three bidentale ligands. Oxidation no. of Cr in K₃[Cr(C₂O₄)₃] is x + 3(−2) + 3(+1) = 0
⇒ x = + 3
Sum of coordination number and oxidation state = 6 + 3 = 9

Q.5. The CFSE for octahedral [CoCl₆]^4– is 18,000 cm^–1. The CFSE for tetrahedral [CoCl₄]^2– will be.

Ans. 8000

CFSE for octahedral and tetrahedral complex is related as

Where Δ_º = CFSE for octahedral complex
Δ_º = CFSE for tetrahedral complex
Δ_º =1800 cm^-1
Δ^t = 4/9 × 18000 = 8000 cm^-1