September 2023

Q. The reaction of equimolar quantities of Fe(CO)5 and OH– gives a complex species X which on further reaction with MnO2 gives species Y. X and Y, respectively, are (A) [Fe(CO)5(OH)]– and Fe2(CO)9 (B) [Fe(CO)4]2– and Mn2(CO)10 (C) [HFe(CO)4]– and Fe2O3 (D) [HFe(CO)4]– and Fe3(CO)12 Ans: [HFe(CO)4]- and Fe3(CO)12

Q. The reaction of PCl3 with PhLi in 1:3 molar ratio yields X as one of the products, which on further treatment with CH3I gives Y. The reaction of Y with n-BuLi gives product Z. The products X, Y and Z, respectively, are (A) [PPh4]Cl, [Ph2P=CH2] and Ph2P(n-Bu) (B) PPh3, [Ph3PI](CH3) and Ph2P(n-Bu)3 (C) PPh3,

Q. For an inverse spinel, AB2O4, the A and B, respectively, can be (A) Ni(II) and Ga(III)                                (B) Zn(II) and Fe(III)  (C) Fe(II) and Cr(III)                    (D) Mn(II) and Mn(III) Ans: Ni(II) and Ga(III)   

Q. Second-order rate constant for the reaction between [Co(NH3)5X]n+ (n = 3 for X = NH3 and H2O; n = 2 for X = Cl–) and [Cr(H2O)6]2+ at room temperature varies with the X as (A) NH3 > H2O > Cl–                  (B) Cl– > H2O > NH3 (C) NH3 > Cl– > H2O                    (D) H2O >

Q. Generally, the coordination number and the nature of the electronic absorption band (f → f transition) of lanthanide(III) ion in their complexes are, respectively, (A) greater than 6 and sharp                            (B) 6 and broad (C) less than 6 and sharp                    (D) greater than 6 and broad Ans: greater than 6 and sharp

Q. Spectroscopic ground state term symbols of cobalt ions in [Co(H2O)6]2+ and [CoCl4]2–, respectively, are (A) 2T1g and 4A2                                                 (B) 4T1g and 4A2 (C) 4T2g and 4T1                                 (D) 2T1 and 4A1 Ans: 4T1g and 4A2

Q. The O2 coordinated to metal ion centres in oxy-myoglobin and oxy-hemocyanin exists, respectively, as (A) superoxide and peroxide (B) superoxide and superoxide (C) peroxide and peroxide (D) superoxide and oxygen Ans: superoxide and peroxide

Q. The symmetry label of valence p orbitals of a metal ion in an octahedral ligand field is (A) t1g  (B) t1u  (C) eg + a1g      (D) t2g Ans: t1u

Q. The lowest energy d → d transition of the complexes follow the order (A) [Cr(H2O)6]3+ < [Cr(NH3)6]3+ < [Cr(CN)6]3– (B) [Cr(CN)6]3– < [Cr(NH3)6]3+ < [Cr(H2O)6]3+ (C) [Cr(CN)6]3– < [Cr(H2O)6]3+ < [Cr(NH3)6]3+ (D) [Cr(NH3)6]3+ < [Cr(CN)6]3– < [Cr(H2O)6]3+ Ans: [Cr(H2O)6]3+ < [Cr(NH3)6]3+ < [Cr(CN)6]3–

Q. The water exchange rates for the complex ions follow the order (A) [V(H2O)6]2+ > [Co(H2O)6]2+ > [Cr(H2O)6]3+ (B) [Cr(H2O)6]3+ > [Co(H2O)6]2+ > [V(H2O)6]2+ (C) [Co(H2O)6]2+ > [Cr(H2O)6]3+ > [V(H2O)6]2+ (D) [Co(H2O)6]2+ > [V(H2O)6]2+ > [Cr(H2O)6]3+ Ans: [Co(H2O)6]2+ > [V(H2O)6]2+ > [Cr(H2O)6]3+