Co-ordination compounds practice · Medium

Option D (Assertion is false, but Reason is true) is correct because the chelate effect makes [Pt(en)2Cl2]2+ more stable than [Pt(NH3)4Cl2]2+.

Option C ([Cr(NH3)3Cl3]) is correct because it is a neutral complex that does not dissociate into ions in aqueous solution, resulting in the lowest electrical conductance.

Option D is correct because the assertion is false (Cu2+ and Cd2+ do form stable complexes with CN-), but the reason is true ([Cu(CN)4]3- is not decomposed by H2S).

The correct answer is D ([Cu(NH3)4]2+ : sp3) because [Cu(NH3)4]2+ has a dsp2 hybridization, not sp3.

Option D (IV $>$ I $>$ II $>$ III) is correct because the wavelength of light absorbed is inversely proportional to the ligand field strength, and the spectrochemical series dictates the order of ligand field strength.

The correct answer is B (${sp}^3, {dsp}^2$) because ${Ni}({CO})_4$ is tetrahedral and ${sp}^3$ hybridized, while $\left[{Ni}({CN})_4\right]^{2-}$ is square planar and ${dsp}^2$ hybridized.

The correct answer is A because both statements are correct, and Statement II correctly explains why SnCl3- acts as a good ligand while SnCl2 does not.

Option C is correct because the assertion is true, but the reason is false. $\left[{PtCl}_2\left(e{n}_2\right)\right]^{+2}$ shows geometrical isomerism (cis and trans), but the trans isomer does not show optical activity because it has a plane of symmetry.

Option B ($4,5,6$) is correct because it provides the correct number of carbonyl ligands for Ni, Fe, and Cr to satisfy the Effective Atomic Number (EAN) rule.

Option D (All of these) is correct because each reagent (BaCl2, AgNO3, PbCl2) will react differently with the two complexes to form different precipitates, allowing them to be distinguished.

Option C ($\left[{Ni}({Cl})_4\right]^{2-}$) is correct because it forms a tetrahedral complex with weak field ligands, resulting in unpaired electrons and thus paramagnetism.

The correct answer is C ([Co(C2O4)3]3-) because in this complex, cobalt has a d6 configuration with strong field ligands, leading to pairing of electrons and a diamagnetic nature.

Option D is the incorrect statement because the red color of ruby is due to the presence of Cr3+ ions, not Co3+ ions, in Al2O3.

Option B (${K}_3\left[{Fe}({CN})_6\right]$) is correct because ${Fe}^{3+}$ has a $d^5$ configuration, resulting in $t_{2g}^5$ in a strong field, not $t_{2g}^6$.

The correct answer is A because [Cr(NH3)6][CO(CN)6] does not show optical isomerism due to the absence of chiral centers and planes of symmetry.

Option B (8 electrons) is correct because in the tetrahedral complex ${K}_2{NiCl}_4$, Ni is in the +2 oxidation state with a d8 electronic configuration.

Option A ($\mathrm{Br}^{-}$) is correct because only the bromide ion ($\mathrm{Br}^{-}$) is outside the coordination sphere and will thus give a positive chemical test.

Option C is correct. Ligands with both π-acceptor and σ-donor character stabilize low oxidation states by synergic bonding.

Option C (3) is correct because for a square planar complex with four different monodentate ligands, there are 3 possible geometrical isomers.

Option B (Ferrocyanide) is correct because Prussian blue, ferric ferrocyanide, is formed by the reaction of ${Fe}^{3+}$ ions with ferrocyanide ions.

Option B (Ionization) is correct because the isomers differ in the ions they produce in solution, with one containing $SO_4^{2-}$ outside the coordination sphere and the other containing $Br^-$ outside.

Option C (Grignard’s reagent) is correct because Grignard reagents (RMgX) have a direct sigma bond between the carbon atom of the alkyl group (R) and the magnesium atom.

Option A (nucleophilic substitution reaction) is correct because ammonia acts as a nucleophile, substituting the halogen atom in the alkyl or benzyl halide.

Option C is correct because both complexes exhibit diamagnetic behavior due to the absence of unpaired electrons after pairing.

Option D (${CO}$) is correct because carbon monoxide (${CO}$) is a $\pi$-acid ligand, meaning it can accept electron density from the metal center through back-bonding.

Option A (1) is correct because the magnetic moment of 1.7 BM corresponds to approximately one unpaired electron in the complex.

Option B (If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion) is correct because 4-Methylhex-2-ene shows stereoisomerism (both geometrical and optical), and the reason is that it can show Geometrical isomerism, but it is not the complete explanation.

Statement-I is false and Statement-II is true because chelating ligands like ethylenediamine (en) provide more stability, and the geometry around Ni2+ in [Ni(en)3]Cl2 is indeed octahedral.

Option A ($d, c, a, b$) is incorrect. The correct order of increasing wavelength of light absorbed is $b, a, c, d$ based on the spectrochemical series and crystal field splitting energy.

Option B is correct because both the assertion and reason are correct, but the reason doesn't fully explain the separation mechanism.