IGNOU BCHCT-137 December 2024 Previous Year Question Paper

Q1.(a) Write the electronic configuration of titanium (At. No. 22) and suggest its most common oxidation states giving reasons. 2

(b) Complete and balance any two of the following reactions : 3 Gii) V(s) + O2x

(g) ——>

Q2.(a) Which of the following ions is coloured ? Give reason : 3 s+ 3+

(b) Explain the role of iron in the biological system.

Q3.(a) Calculate the magnetic moments of [Co(H,0), ” and TiCh. 2

(b) Why is the separation of lanthanoids difficult ? List two important methods for their separation.

Q4.(a) Write the IUPAC names of the following compounds :

Q5.Ks[Fe(CN), NO]

(i) [CoCl.CN.NO,.(NH,), |

(b) Determine the oxidation state and coordination number of the central metal ion in any one of the following compounds : en is 1, 2-diaminoethane Gi) [Pt(NH,),Cl, | Be. .

Q6.(a) The complex [Co(en), | is diamagnetic but [CoF, } is paramagnetic and has four unpaired _ electrons. Explain these observations and deduce the structure of these complexes on the basis of Valence Bond Theory (VBT). 3

(b) Draw the structures of cis-[Co(NHs3)4Clz]* and trans-[Co(NH3)4Cly]*.

Q7.(a) Write the formula of the following : 2

(06) Dichlorido bis (1, 2-diaminoethane) rhodium (IID ions Gi) Bis (benzene) chromium

(0)

(b) Compare the chemistry of actinoids with that of lanthanoids with special reference to any two of the following : 3 @)_ Electronic configuration

(ii) Oxidation state

(iii) Atomic and ionic sizes

Q8.(a) Calculate the crystal field stabilization energy of [ Fe(OH, )] . 2

(b) Identify the presence and absence of Jahn- Teller distortion in [Co(NH,), |” and Ni(II) ions. Justify your answer. 3 Part—B (Marks : 25) (States of Matter and Chemical Kinetics)

Q9.(a) Give two differences between order and molecularity of the reaction. 2

(b) Find the unit of rate constant (k) for a second order reaction. 1

(c) Find the order of reaction whose rate constant has unit mol! L32 s+, 1

(d) Give any two factors that affect the rate of a chemical reaction.

Q10.(a) A reaction is first order in A and second order in B:

(i) Write the differential rate equation. 1 Gi) How is the rate affected when the concentration of A is doubled and that of B is tripled ? 2

(b) The rate of a chemical reaction doubles for an increase of temperature from 298 K to 308 K. Calculate the activation energy. (log 2 = 0.30)

Q11.(a) State Charles’ law. 1

(b) Can — 273.15°C temperature be achieved ? Justify your answer. 1

(c) What is the pressure exerted by 2 g of hydrogen gas at 27°C if it occupies a volume of 100 cm?. 1

(d) Asample of nitrogen gas occupies a volume of 320 cm? at temperature 273 K and 1 atm. pressure. Calculate the volume, when the temperature is 66°C and pressure is 0.825 atm.

Q12.(a) State postulates of kinetic theory of gases.

(b) What is the effect of temperature on Maxwell-Boltzmann distribution ? Show with the help of a graph.

Q13.(a) Give the formula used in drop weight and drop number method to determine the surface tension of a liquid. Calculate the ratio of number of drops of water and benzene if the values of density for water [71 BCHCT-137 and benzene are 1.00 kg dm° and 0.88 kg dm- respectively. Their surface tension values are 0.0728 Nm! and 0.0289 Nm respectively at 298 K. 3

(b) What is the effect of temperature on the viscosity of a liquid.

Q14.(a) What is unit cell ? 1

(b) What are London forces ? 1

(c) Name any two fundamental laws of crystallography. 1

(d) Calculate the Miller indices of crystal planar which cut through the crystal axes at (2a, 30, c).

Q15.Consider the reaction : A— P The change in the concentration of A with time is shown in the following plot : 5 [Alt

(i) Predict the order of the reaction.

(ii) What are the units of rate constant ?

(iii) Give the relationship between k and t,,..

(iv) How is the slope of the above line related to the rate constant of the reaction ?

(v) What is the intercept of the above line equal to? (@) Ks{Fe(CN), NO] Gi) [CoCl.CN.NO,.(NH,), | Gi) [Pt(NH,), Cl, | [Alt