IGNOU BCHCT-135 June 2025 Previous Year Question Paper

Q1.(a) Give the nature of process occurring on anode in a galvanic cell. 1

(b) The conductivity of a saturated solution of CaFz at 18°C was found to be

Q2.2 x 10° S cm”!. The conductivity of water used for making the solution was

Q3.0 x 10-6 S cm. The molar ionic conductivities at infinite dilution of Ca2+ and F- ions are 104.0 and 48.0 S cm? mol!, respectively. What is the solubility and solubility product of CaF2?

Q4.(a) State and explain Raoult’s law. 2

(b) Sketch a plot of chemical potential

(1) against temperature (T) for solid, liquid and gaseous forms of a pure substance. Comment on the stability of phases. Indicate the melting and boiling points in this plot. What thermodynamic criterion is used to locate melting and boiling points ?

Q5.(a) Name an electrolyte other than KCl that can be used in salt bridge. Give reasons for your answer. 1

(b) Using the reactions, ‘e" + 3e > Fe हा =-0.036V Fe +2e>Fe E° ५, =-0.440V Fe" /Fe calculate the standard _ electrode potential for the reaction given below : 2 Fe +e Fe”*

(c) Can there be four phases in equilibrium for a one-component system ? Justify your answer.

Q6.(a) What is meant by transference number of ions ? Describe the moving boundary method used to determine experimentally the transport number of ions. 3

(b) The molar conductances of sodium acetate, hydrochloric acid and sodium chloride at infinite dilution are 91.0,

Q7.16 and 126.45 S cm? mol, respectively at 25°C. Calculate the molar conductance at infinite dilution for acetic acid.

Q8.(a) Two liquids A and B form an ideal solution at 300 K. The vapour pressure of a solution containing 1.0 mol of A and

Q9.0 mol of B at 300 K is 2.0 x 105 Pa. When 1.0 mole of B is added to the solution, the vapour pressure of the solution is 2.1 x 105 Pa. Calculate the vapour pressures of A and B in the pure state. 3

(b) State Nernst’s distribution law. Also give its limitations.

Q10.(a) Draw and_ explain conductometric titration curve for the titration between formic acid and NaOH. 2

(b) Define conductivity and give any four factors affecting the conductivity.

Q11.(a) What is the effect of the following on the Critical Solution Temperature (CST) of phenol water system ? 2

(i) Addition of 0.1 M KCl

(ii) Addition of succinic acid

(b) During the thermal analysis, the cooling curve of a eutectic mixture at eutectic composition has no break points. Explain. 1

(c) Calcium carbonate on heating in a closed vessel decomposes as per the following equation : CaCO3(s) = CaO(s) + COQ

(g) How many components and phases are there in the system ? 2 Part-B (Marks : 25)

Q12.Complete the following reactions : 5 CH)CH; @ 1.KMn04,0H™,A

Q13.H*,H20 H3C—N-CH: ५५ O NaNO2,HCL_ a) O orc Gi) oO Bry,NaOH, HO (80 iv) (CHOH) dil.HNO3 | 180९: Ht (० R-C-OH+H*°OCH,

Q14.Explain the mechanism of Hell-Volhard- Zelinsky reaction.

Q15.@) How would you convert aniline into para-nitroaniline ? Give the reactions involved. 3

(i) What are disaccharides ? Give one example.

Q16.@ How would you distinguish between primary, secondary and tertiary amines using Hinsberg test ? Give the reactions involved. 3 Gi) How will you convert 2, 4, 6-tribromo- aniline to 1, 3, 5-tribromobenzene ?

Q17.(i) Differentiate between epimers and anomers. 2 Gi) How are anomers formed ? Draw structure for the anomers of glucose.

Q18.Describe Merrifield solid phase synthesis for preparation of the dipeptide gly-ala with the help of reactions.

Q19.(i) Give important features of o -helix and B -pleated sheet structures of proteins. Gi) Propanoic anhydride, A upon hydrolysis gives compound B. B on treating with PCls gives C, which gives nucleophilic addition-elimination reaction with aniline and forms product, D. Identify B, C and D. 3 Fe +3e > Fe E® 3, =—0.036V Fe°"/Fe Fe2* F ० '€/ +26 -> Fe EY 2+ re =-0.440V Fe +e Fe”*

Q20.(&) Witte ame sik NaOH & sta agar & CH>CH

(3)

Q21.OQ 1.KMn04,0H7,A

Q22.H*,H,O H3C—N-CH: i) O NaNO», HCl ii) oO By NaOl. 0 CHO Gv) (CHOH), —SLHNOs_, CH,0H 1802 Ht (० R-C-OH+H°OCH,

Q23.(i) West st a-agsfertt ak p-cefa site