AIIMS Chemistry Coordination Compounds Class 12 Questions

Assertion : d⁵ configuration is more stable than d⁴ Reason : d⁵ has more exchange energy as compared to d⁴ because 10 & 6 exchanges are possible in d⁵ & d⁴ respectively.

Which of the following complex is optically inactive (1) [RhCl(CO)(PPh₃)(NH₃)] (2) [Fe(C₂O₄)₃]³⁻ (3) [Fe(en)₂Cl₂] (4) [Pd(en)₂Cl₂]

Correct increasing order for the wavelength of absorption in the visible region for the complexes of Co³⁺ is: (1) [Co(CN)₆]³⁻, [Co(NH₃)₆]³⁺, [Co(NH₃)₅(H₂O)]³⁺[Co(NH₃)₅Cl]²⁺ (2) [Co(CN)₆]³⁻, [Co(NH₃)₅(H₂O)]³⁺[Co(NH₃)₅Cl]²⁺ [Co(NH₃)₆]³⁺, (3) [Co(NH₃)₅]²⁺, [Co(CN)₆]³⁻, [Co(NH₃)₅(H₂O)]³⁺[Co(NH₃)₅Cl]²⁺ (4) [Co(NH₃)₅Cl]²⁺, [Co(NH₃)₅(H₂O)]³⁺, [Co(NH₃)₄]³⁺, [Co(CN)₆]³⁻

In coordination complex [Co(C₂O₄)₃]³⁻, Co³⁺ acts as a central metal ion. Co³⁺ shows d²sp³ hybridization hence all the electrons are paired and diamagnetic in nature. Thus, it is a low spin complex.

Which of the following does not give ppt with CrO₄²⁻

The reaction of Ag⁺ with excess of sodium-thiosulphate is given below. Ag⁺ + Na₂S₂O₃ → [Ag(S₂O₃)₂]³⁻. This complex possesses^{-3} charge. The coordination number for Ag is 2 which correspond to sp hybridization and linear geometry.

Which of the following complexes has maximum CFSE?

The oxidation state of Ni in the complex, [Ni(CO)₄] is calculated below. x + 4(0) = 0, x = 0. The electronic configuration of Ni is [Ar]₃d⁸4s²4p⁰. The orbital diagram of nickel in the presence of strong field ligand CO is shown below.

In Fe(CO)₅ and Cr(CO)₆, how many CO ligands can be replaced by NO?

Correct increasing order for the wavelength of absorption in the visible region for the complexes of $\text{Co}^{3+}$ is:

$\text{C} + \text{O}_2(\text{g}) \rightarrow \text{CO}_2 \dots\dots(\text{i}); \quad \Delta\text{H} = -393 \text{ kJmol}^{-1}$ $\text{H}_2 + \frac{1}{2}\text{O}_2 \rightarrow \text{H}_2\text{O}, \dots\dots(\text{ii}); \quad \Delta\text{H} = -287.3 \text{ kJmol}^{-1}$ $2\text{CO}_2 + 3\text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \dots\dots(\text{iii}); \quad \Delta\text{H} = 1366.8 \text{ kJmol}^{-1}$ Find the standard enthalpy of formation of $\text{C}_2\text{H}_5\text{OH}(\text{l})$

Chloro compound of vanadium has only spin magnetic moment of 1.73 BM. This vanadium chloride has the formula:

K₃[Fe(CN)₆] (potassium ferricyanide) Ω.S = +3 therefore, it is slightly paramagnetic in nature, but K₄[Fe(CN)₆] O.S. = +2 potassium ferrocyanide has all the paired electrons; therefore, it is diamagnetic in nature.

For the ions $\text{Zn}^{2+}$, $\text{Ni}^{2+}$ and $\text{Cr}^{3+}$ which among the following statements is correct? (Atomic number of Zn = 30, Ni = 28 and Cr = 24)

The IUPAC name for the complex $[\text{Co}(\text{NO}_2)(\text{NH}_3)_5]\text{Cl}_2$ is:

The molar ionic conductance of the octahedral complexes: (i) $\text{PtCl}_4 \cdot 5\text{NH}_3$ (ii) $\text{PtCl}_4 \cdot 4\text{NH}_3$ (iii) $\text{PtCl}_4 \cdot 3\text{NH}_3$ (iv) $\text{PtCl}_4 \cdot 2\text{NH}_3$ Follow the order

[Fe(H₂O)₅NO]²⁺ is a complex formed during the brown ring test for NO₃⁻ ion. In this complex,

When ammonia reacts with Cr³⁺ which is present in aqueous medium, it forms a coordination complex [Cr(NH₃)₆]³⁺ having coordination number 6 as shown below: [Cr(H₂O)₆]³⁺ + 6NH₃ → [Cr(NH₃)₆]³⁺

[Cr(CO)₆] + NO (excess) → Product

The complex, V(CO)₆ can be easily reduced to the form [V(CO)₆]⁻.

Which of the following give good synergic bond with metal

Assertion: [Co(NH₃)₆]³⁺ → [Co(NH₃)₅H₂O]³⁺ colour continuously changes. Reason: Larger wavelength will be absorbed

When an aqueous solution of copper (II) sulphate is saturated with ammonia, the blue compound crystallises on evaporation. The formula of this blue compound is:

For [Cr(H₂O)₆]²⁺ Oxidation state is equal to 2. Electronic configuration of Cr²⁺ is [Ar]¹⁸ 4s¹3d⁵ CFSE value is –0.6Δ₀ For [Cr(H₂O)₆]³⁺ Oxidation state is equal to 3. Electronic configuration of Cr³⁺ is [Ar]¹⁸ 3d³ CFSE value is –1.2Δ₀ Therefore, this shows that CFSE value becomes different while converting and colour remains the same.

Select correct match

The coordination number of platinum in zieses salt is 4 not five as shown below.

Assertion: [Co(NH₃)₆]³⁺ and [Co(en)₃]³⁺ are more stable complex. Reason: They are low spin complex.

Zeise’s Salt

Cis-[Ni(H₂O)₄(NH₃)₂]²⁺ and facial [Ni(H₂O)₃(NH₃)₃]²⁺ shows the optical isomerism. This is shown below,

There is no vacant d-orbital are resent in outermost shell of "Be". So, "Be" and "Al" can form BeF₄²⁻ and AlF₆³⁻ but not BeF₆³⁻.

Assertion: Both Be and Al can form complexes such as BeF₄²⁻ and AlF₆³⁻ respectively. BeF₆³⁻ is not formed. Reason: In case of Be, no vacant d-orbital are present in its outermost shell.

Assertion (A): Complexes of $\text{MX}_6$ and $\text{MX}_5\text{L}$ type ($\text{X}$ and $\text{L}$ are unidentate) do not show geometrical isomerism. Reason (R): Geometrical isomerism is not shown by complexes of coordination number 6.

Select the correct statement.

Assertion : Co[Hg(SCN)₆] and Hg[Co(SCN)₆] are isomers. Reason : SCN⁻ is a stronger ligand as compared to NCS⁻

Consider the following arrangements of the octahedral complex ion [Co(NH₃)₄Cl₂]⁺. Which of the following statements is false?

[Fe(H₂O)₅NO]²⁺ is a complex formed during the brown ring test for NO₃⁻ ion. In this complex.

Which of the following metal ion forms unstable complex with CN⁻?

Assertion : EDTA forms complex with divalent metals of 3d-series in the ratio of 1:1. Reason : EDTA has 4 –COOH groups.

Assertion : In a mixture of CdCl₂ and CuCl₂, Cd²⁺ gets precipitated in presence of KCN by H₂S. Reason : The stability constant of [Cu(CN)₄]²⁻ is greater than [Cd(CN)₄]²⁻.

Assertion: Aq. solution of CoCl₂ is pink in colour. It turns blue in presence of conc. HCl. Reason: It is due to the formation of [CoCl₄]²⁻.

Magnetic moment of Cr²⁺ is nearest to

Assertion: $\text{F}^-$ ion is a weak ligand and forms outer orbital complex. Reason: $\text{F}^-$ ion cannot force the electrons of $d_{z^2}$ and $d_{x^2 - y^2}$ orbitals of the inner shell to occupy $d_{xy}$, $d_{yz}$ and $d_{zx}$ orbitals of the same shell.

Assertion: $[\text{Fe}(\text{H}_2\text{O})_5\text{NO}]\text{SO}_4$ is paramagnetic. Reason: The Fe in $[\text{Fe}(\text{H}_2\text{O})_5\text{NO}]\text{SO}_4$ has three unpaired electrons.

The wavelength of light absorbed is shortest in

Which of the following is diamagnetic?

Assertion : AgCl is more soluble in NH₃ than in water. Reason : Ammonia is more polar than water.

Match list I with list II and select the correct answer using the codes given below the lists.

A complex PtCl₄.5NH₃ shows a molar conductance of 402 Ω⁻¹ cm² mol⁻¹ in water and precipitates three moles of AgCl with AgNO₃ solution. The formula of the complex is

Assertion: The degree of complex formation in actinides decreases in the order M⁴⁺ > MO₂²⁺ > M³⁺ > MO₂⁺. Reason: Actinides form complexes with π-bonding ligands such as alkyl phosphines and thioethers.

Assertion: A complex ion with chemical formula is named as tetrakis (ethylenediamine)μ-hydroxo-μ-imido dicobalt (III) ion. Reason: In naming polynuclear complexes i.e., containing two or more metal atoms joined by bridging ligands, the word μ is added with hyphen before the name of such ligands.