DPP-39 to 40 Physical Cheistry

DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 39 to 40 Class : XIII Course DPP No.39 DPP No.1 Total Marks : 41 Max. Time : 41 min. Single choice Objective ('–1' negative marking) Q.1 to Q.7 (3 marks 3 min.) [21, 21] Subjective Questions ('–1' negative marking) Q.8 to Q.12 (4 marks 4 min.) [20, 20] 1. A complex with the molecular formula CrCl3.6H2O is such that 1/3 of the total chloride is precipitated by adding AgNO3 to its aqueous solution. Then which of the following is its best representation : (1) CrCl3.6H2O (2) [Cr(H2O)3 Cl3].3H2O (3) [CrCl2(H2O)4]Cl.2H2O (4) [CrCl(H2O)5]Cl2.H2O 2. Match list  with list  and select the correct answer : List (Ι) (Equiv. conductance at infinite dilution) List (ΙΙ) (Formula) (A) 229 (B) 97 (C) 404 (D) 523 The code : (a) [Pt(NH3)5Cl]Cl3 (b) [Pt(NH3)3Cl3]Cl (c) [Pt(NH3)4Cl2]Cl2 (d) [Pt(NH3)6]Cl4 A B C D (1) e a b d (2) a c d b (3) a d c b (4) c b a d 3. Which of the following complex ions obeys Sidgwick’s effective atomic number (EAN) rule ? (1) [Fe(CN) ]3– (2) [Fe(CN) ]4– (3) [Cr(NH ) ]3+ (4) [Ni(en) ]2+ 4. In which of the following complexes the effective atomic number is not equal to the atomic number of a inert gas : (1) Ni(CO) (2) [Co(NH ) ]3+ (3) [Fe(CN) ]4– (4) [CuCl ]– 4 3 6 6 2 5. A coordination compound of cobalt has the molecular formula containing five ammonia molecules, one nitro group and two chlorine atoms for one cobalt atom. One mole of this compound produces three moles of ions in an aqueous solution. The aqeuous solution on treatment with an excess of AgNO3 gives two moles of AgCl as a precipitate the formula of this complex would be : (1) Co[NH3)4NO2Cl][NH3Cl] (2) [Co(NH3)Cl] [ClNO2] (3) [Co(NH3)5NO2]Cl2 (4) [Co(NH3)5] [(NO2)2Cl2] 6. Which of the following complex ions obeys Sidgwick’s effective atomic number (EAN) rule ? (1) [Fe(CN) ]3– (2) [Fe(CN) ]4– (3) [Cr(NH ) ]3+ (4) [Ni(en) ]2+ 7. In which of the following complexes the effective atomic number is not equal to the atomic number of a inert gas : (1) Ni(CO) (2) [Co(NH ) ]3+ (3) [Fe(CN) ]4– (4) [CuCl ]– 4 3 6 6 2 8. Two compounds have the molecular formula, Co(H2O)4(NO2)3. In aqueous solution one of these compounds does not conduct electricity while the other does. Write the possible structures of these two compounds. 9. A coordination compound has the formula CoCl3.4NH3. It does not liberate NH3 but precipitates Cl– ions as AgCl. Give the IUPAC name of the compound and write its structural formula. 10. Explain the following, giving appropriate reasons. (i) Out of K4 [Fe(CN)6] and K3 [Fe(NH3)6] solutions, the former has higher value of molar conductivity. (ii) [Pt(NH3)2 Cl2] and [Pt(NH3)6] Cl4 differ in their electrolytic conductance (iii) The value of molar conductivity of the aqueous solution of [CoCl3 (NH3)3] is zero. 11. Arrange the following complexes in the increasing order of their electrical conductivity : [Co(NH3)3 Cl3], [Co(NH3)6] Cl3 and [Co(NH3)5 Cl]Cl. 12. The compound CoCl3.4NH3 contains only one Cl– ion that is precipitated immediately on the addition of Ag+ ions. Draw the structure of the compound on the basis of Werner’s coordination theory. DPP No.40 DPP No.2 Total Marks : 33 Max. Time : 33 min. Single choice Objective ('–1' negative marking) Q.1 to Q.8 (3 marks 3 min.) [24, 24] Comprehension ('–1' negative marking) Q.9 to Q.11 (3 marks 3 min.) [9, 9] 1. It is experimentally found that the compound K3[Ni(CN)5] shows an decrease in its weight when placed in a magnetic balance and four metal–ligand bond lengths are equal but the rest is different. Then which of the following set of informations is correct : (i) The transition metal is sp3d hybridised (ii) The net dipole moment of complex is  zero (iii) The transition metal is dsp3 hybridised (iv) The net dipole moment of the complex is zero (v) The complex ion is trigonal bipyramidal (vi) The complex ion is square pyramidal (1) (i),(ii),(v) (2) (ii),(iii),(vi) (3) (iii),(iv),(v) (4) none of these 2. When the complex K6 [(CN)5 Co–O–O–Co(CN)5] is oxidised by bromine into K5[(CN)5 Co–O–O–Co(CN)5]. Then which of the following statements will be true about this change: (In both compound Co is in + 3 oxidation state) (1) Co() is oxidised in Co() (2) The O–O bond length will increase (3) The O–O bond length will decrease (4) ‘A’ & ‘B’ both are correct 3. The crystal field-splitting for Cr3+ ion in octahedral field increases for ligands I–, H O, NH , CN– and the order is: 2 3 (1) I– < H O < NH < CN– (2) CN– < I– < H O < NH (3) CN– < NH < H O < I– (4) NH < H O < I– < CN– 2 3 2 3 3 2 3 2 4. In which of the following configurations will there be the possibility of both para and diamagnestism, depend- ing on the nature of the ligands? (1) d7 (2) d3 (3) d6 (4) d5 5. The complex for which the calculation of crystal field splitting can be most easily done, by knowing its absorption spectrum, will be : (1) [TiCl6]2– (2) [Fe(H2O)6]2+ (3) [Ti(CN)6]3– (4)[CoF6]3– 6. In which of the following complex ion, the metal ion will have t6 ,e0 configuration according to CFT: (1) [FeF ]3– (2) [Fe(CN) ]3– (3) [Fe(CN) ]4– (4) None of these 6 6 6 7. The correct order for the CFSE (numerical value) for the following complexes is Complex P Q R S Formula [CoF ]3– [Co(CN) ]3– [Co(NH ) ]3+ [Co(H O) ]3+ 6 6 3 6 2 6 (1) P > Q > R > S (2) Q > R > S > P (3) S > R > P > Q (4) R > Q > P > S 8. In the reaction : [Ag(CN) ]– + Zn  the complex formed will be : (1) Tetrahedral (2) square planar (3) octahedral (4) triangal bipyramidal Comprehension : (Q.9 to Q.11) Werner performed two experiments : Expt-1 : He prepared a compound X by reacting KCl with PtCl4. The compound X didn't give any ppt. with AgNO3 but gave electrical conductance corresponding to 3 ions. Expt-2 : He took 0.319 g of CrCl3.6H2O and passed through a cation exchange resin & the acid coming out required 28.5 ml of 0.125 M NaOH. Hence 9. The formula of the compound X is : (1) [KPtCl]Cl2 (2) K2[PtCl4] (3) K2[PtCl6] (4) K[PtCl4] 10. The hybridization in K2[PtCl6] is : (1) sp3 (2) d2sp3 (3) sp3d2 (4) dsp3 11. The complex CrCl3.6H2O can be rightly represented as : (1) [Cr(H2O)4Cl2]Cl (2) [Cr(H2O)6]Cl3 (3) [Cr(H2O)3Cl3]3H2O (4) [Cr(H2O)5Cl]Cl2 ANSWER KEY DPP No.-37 1. 3 2. 4 3. 2 4. 4 5. 1 6. 1 7. 2 8. 1 9. 4 10. 2,3 11. k = k3K2 DPP No.-38 1. 4 2. 3 3. 1 4. 3 5. 4 6. 1 7. 1,2,3 10. 4 11. 4 12. 1 13. 1,2,3,4