Colour and magnetic moment of complexes

27 questions on Colour and magnetic moment of complexes from the Coordination Compounds chapter: 6 NEET level, 11 JEE Main, 10 JEE Advanced. Each one opens with its answer and solution.

• Assertion (A): [Zn(H2O)6]^2+ is colourless. Reason (R): Zn^2+ is d^10, so no d-d transition is possible. JEE Main level
• Take H2O and F- as weak field (high spin) and CN- as strong field (low spin). Select the correct comparisons. JEE Advanced level
• Assume strong field CN- gives low spin and weak field H2O gives high spin. Select the diamagnetic species. JEE Main level
• What is the spin-only magnetic moment, in BM, of the complex ion in K3[Fe(CN)6]? Take CN- as strong field. Give the answer to two decimal places. JEE Main level
• The complex [Ni(CO)4] is NEET level
• Take [NiCl4]^2- as tetrahedral and [Ni(CN)4]^2- as square planar. Select the correct statements. JEE Main level
• Select the correct statements about tetrahedral complexes (CFSE in units of Delta_t, pairing ignored, high-spin filling). JEE Advanced level
• Select the complexes in which no d-d transition is possible (expected to be colourless). JEE Advanced level
• What is the spin-only magnetic moment, in BM, of the complex ion in K3[Mn(CN)6]? Treat CN- as strong field. Give the answer to two decimal places. JEE Advanced level
• Select the species that have exactly two unpaired electrons (tetrahedral for the chlorido complex). JEE Main level
• A d^6 octahedral ion has Delta_o = 19800 cm^-1 and mean pairing energy P = 17600 cm^-1. The energy of each spin state is measured from the barycentre, adding P ... JEE Advanced level
• The colour of [Ti(H2O)6]^3+ is mainly due to NEET level
• Take F- as weak field (Co(III) high spin) and NH3 as strong field (Co(III) low spin). Select the correct statements about [CoF6]^3- and [Co(NH3)6]^3+. JEE Advanced level
• A d^4 octahedral complex has Delta_o = 21000 cm^-1 and pairing energy P = 28000 cm^-1. Assuming the single d-d band lies at Delta_o, the spin-only moment and th... JEE Advanced level
• The number of unpaired electrons in the high-spin octahedral ion [Fe(H2O)6]^3+ is NEET level
• Taking H2O as weak field (high spin) and CN- as strong field (low spin), and ignoring pairing energy, the ratio of CFSE of [Fe(H2O)6]^2+ to that of [Fe(CN)6]^4-... JEE Advanced level
• An octahedral complex K_x[FeF6] has iron in the +2 or +3 state. F- is a weak-field ligand and the spin-only moment is 4.90 BM. The oxidation state of Fe and its... JEE Advanced level
• Given the field strength order CN- > NH3 > H2O > F-, which complex absorbs its d-d band at the shortest wavelength? JEE Main level
• Taking F- as a weak-field ligand (high spin), the spin-only magnetic moment of [CoF6]^3- is JEE Main level
• Match each complex in Column I with its number of unpaired electrons in Column II (H2O is weak field, CN- is strong field). Column I: P [Fe(H2O)6]^2+; Q [Fe(CN)... JEE Main level
• For the same metal ion in an octahedral field, which ligand gives the largest crystal field splitting Delta_o? NEET level
• A complex absorbs only orange light from white light. Using the usual colour wheel of complementary colours, the colour seen is JEE Main level
• Which aqueous complex ion is expected to be colourless? NEET level
• The spin-only magnetic moment of [Ni(NH3)6]^2+ is JEE Main level
• A nickel(II) complex [NiX2L2] (X = halide, L = phosphine) exists in only one isomeric form and has a spin-only moment of 2.83 BM. The geometry and hybridisation... JEE Advanced level
• Ignoring pairing energy, the crystal field stabilisation energy of the low-spin octahedral ion [Fe(CN)6]^4- is JEE Main level
• The spin-only magnetic moment of [Cr(H2O)6]^3+ is NEET level