IGNOU BCHCT-137 June 2025 Previous Year Question Paper

Q1.(a) An aqueous solution of which of these is coloured and why : Copper (II) sulphate, Zine (ID) sulphate ? श्र (७) Why is the separation of lanthanoids difficult ? Which method is used? श्र

Q2.(a) Among the two species [CoF,]* and [Co(NH,),] wich will be inner orbital which will be inner orbital and which will be outer orbital ? What will be the magnetic behaviour ? 3

(b) Which of the two ions Fe(II) or Cri) would be easily oxidised ? 2 Fe* +e = Fe" +0.77V (Standard reduction potential (E°) Cr +e = Cr” -0.41V (Standard reduction potential (E°)

Q3.(a) Write the formula for the following complexes : Dichloridobis (1, 2-diaminoethane) Cobalt (IIT) ion. Draw its geometrical and _ optical isomers. 3

(b) Write the IUPAC names for the following : 2 @ Hg[Co(NCSs),]

(ii) [Pt(NHs)4(Br)(Cl)]SO

(4)

Q4.(a) Explain why octahedral complexes of Copper (II) show tetragonal distortion. 3

(b) Write the formula of the following: 2 @ Potassium hexacyanidonitrosyl ferrate

(1) Gi) Pentaammine—aquacobalt (dD chloride

Q5.(a) Give the name and symbol for the elements having the valence configuration 4s? 3d°; 4s! 3d19; 5s? 4d.

(b) Write the valence electronic configuration of Fe?* and Zn?*.

Q6.(a) Calculate the Crystal-Field Stabilization Energy (CFSE) and spin- only magnetic moment of [Fe(OH2)¢]?*. 3

(b) Mention the isomerism depicted in the following pairs : 2 NH. 7 Cc 7 2 ne Cc Cc @ [on.coC | Pees. | 19 and C\(NE),Co_ _-Co(NH;),Cl Cl, रे CH;-NH, | on CH, Gi) । Pt | (0- 0 O— CO CH,—NH, y Oo — CO and | Pt | Zz ® (0- 0 NH, —CH,

Q7.(a) What are the two series of inner transition elements ? Where are they placed in the periodic table ? 3

(b) Draw the splitting diagram of orbitals of a metal in tetrahedral field. 2 Part—B (Marks : 25) (States of Matter and Chemical Kinetics)

Q8.(a) Can -273.15°C temperature be achieved ? 1

(b) An ideal gas occupying 152 dm3 at 15°C and 0.98 atm. pressure is placed in an evacuated vessel of volume 456 dm*. To what degree Celsius the vessel be heated so that its pressure be 0.98 atm. ?

(c) Derive ideal gas equation, using gas laws.

Q9.(a) Give the postulates of kinetic molecular theory of gases. 3

(b) What is the effect of temperature on the viscosity of gases ?

Q10.(a) What is total attractive interaction? 3

(b) Define surface tension and give its unit. What is the effect of adding surfactant on surface tension ?

Q11.What are stoichiometric defects ? Give the classification of stoichiometric defect and explain them.

Q12.Consider the reaction : A—-,p The change in the concentration of A with time is shown in the following plot : [A] PD

(a) Predict the order of the reaction. 2

(b) Derive the expression for the time required for the completion of the reaction.

Q13.(a) For the given reaction : A+B>C Rate increases four times if concentration of A is kept constant while concentration of B is doubled. Rate increases 32 times if A is doubled and B is also doubled. Find out the order of the reaction. 4

(b) What is the unit of rate constant (R) for first order reaction ?

Q14.(a) What are dipole-dipole interaction ? Give example. 2

(b) What is radius ratio ? 1

(c) How many crystal system and Bravais lattice are there in solids ?

Q15.(क) [CoF,]* 2 [Co(NH,),]* Feet F ara F Fe* +e = Fe" +0.77V Cr* +e = Cr™ -0.41V

(i) [Pt(NHs)s(Br)(Cl)]SO4 NH. . owe ८

(i) Jastny.coC evesttc1, |Cl NH. ८ cf 8c cle [crest 0€ ० ०00 0, CH,—NH, 0 —CO cO—O~ ‘NH>-CH, (@) WH ares Ha St 15°C FM 0.98 atm. Ta K

Q16.98 atm. @ ? 2 A—?.4p A+B>C