IGNOU BCHCT-135 December 2023 Previous Year Question Paper

Q1.(a) Give one example of liquid pair that forms a nearly ideal solution on mixing. 1

(b) The conductivity of a saturated solution of AgCl at 298 K was found to be

Q2.41 x 10-6 S cm. The water used for dissolving AgCl had a conductivity of

Q3.6 x 10-6 S cm~!. If the molar conductivity at infinite dilution for AgCl at 298 K is given as 138.2 S cm mol-, calculate the solubility product of AgCl at 298 K.

Q4.(a) What are concentration cells ? Give an example of an electrode concentration cell.

(b) How would the increase in pressure affect p us. T curves for a pure substance ? Draw a schematic diagram indicating the same.

Q5.(a) Write the cell diagram for a galvanic cell in which the following reaction takes place : Cell reaction : Zn(s) + 2 Agt(aq) > Zn?*(aq) + 2 Ag(s) Assume that potassium nitrate is used as electrolyte in the salt bridge and the concentrations of zinc ions and silver ions are c,; and Cy, respectively. 3

(b) List different methods based on EMF measurement that can be used for the determination of pH of aqueous solutions.

Q6.In determination of transference numbers of HCl by moving boundary method, a 0.1 M solution of HCl was taken in a cell having area of cross-section of 1.25 cm2. At the end of the experiment, boundary moves by 7.5 cm and

Q7.12 g of silver was deposited on the cathode of silver coulometer. Calculate the transference numbers of H* and Cl ions.

Q8.(a) An azeotropic mixture of HCl and HzO contains 20.2% HCl. Calculate its molality.

(b) State Nernst’s distribution law.

Q9.(a) What are congruently and incongruently melting compounds ? 4

(b) Write down the name of any one salt which is used in the preparation of a salt bridge.

(1)

Q10.(a) What is meant by triple point ? 1

(b) What is the criteria for phase equilibrium in a one-component system containing three phases in equilibrium at constant temperature and pressure ? 2

(c) Give any two applications of solvent extraction. 2 Part—B (Marks : 25) (Functional Group Organic Chemistry-I])

Q11.Briefly explain any two of the following reactions giving the chemical equations : 5 G) Hoffmann bromamide reaction

(i) Gabriel phthalimide synthesis Gii) Hell-Volhard-Zelinsky reaction

Q12.Complete any five of the following reactions : 1x5=5 . Ht

(i) CH,COOH + H'80c,H; ———= ? Gi) O + Bre water > ?

(iii) CyyH01,+ HO > ? Sucrose CHO

(iv) (CHOW,+ 3C,H;NHNH, > ? CH 0H ic OH w) 2 Cx x +H; N- CH ~ COO™ Ninhydrin pH=9 9 | Water CH) — OH

Q13.How will you distinguish between primary, secondary and tertiary amines using Hinsberg test ? Give the reactions involved.

Q14.(a) Give reactions involved for the conversion of the following : 2+2 @) aniline to chlorobenzene Gi) aniline to para-nitroaniline

(b) Name the products obtained by hydrolysis of maltose.

Q15.(a) What is isoelectric point of an amino acid ?

(b) How will you separate a mixture of amino acids by electrophoresis ? 2

(c) Sucrose is a non-reducing sugar. Explain.

Q16.(a) Explain Sanger method for N-end group analysis of a peptide giving reactions involved. 4

(b) What are the monosaccharides present in cellulose ?

Q17.(a) Explain Kiliani-Fischer synthesis by starting with D-(+)-arabinose. Write the reactions involved in the synthesis. 4

(b) How many peptide bonds are present in a tetrapeptide ? 1 TAM W Alek Ate 138.2 S cm mol Zn(s) + 2 Ag* (aq) > Zn?*(aq) + 2 Ag(s) eo Fl

Q18.1. 0.

(iv) (80 (CHOH),+ 3CgH;NHNH, > ? CH OH ic OH +

(v) 2 Cx +H, N- CH - COO- xX OH ° | ‘i 0 fa Ninhydrin pHe9 |. 9 CHO

(vi) (CHOH) an 2 CH) - OH

Q19.1. 0.