IGNOU BCHCT-135 June 2022 Previous Year Question Paper

Q1.Explain the process of steam distillation using a labelled diagram.

Q2.(a) How many components are there in a system in which ethanol and acetic acid react to form ethyl acetate and water ? 2

(b) For vaporisation equilibrium, the Clapeyron equation is as follows : dp _ vay dT TA. Vv ‘vap Using this equation, derive Clausius-Clapeyron equation for vaporisation. Also state the assumptions made by Clausius.

Q3.(a) State Konowaloff’s rule. 1

(b) Define eutectic mixture. 1

(c) Draw and explain the cooling curve for a mixture of two components constituting a simple eutectic system.

Q4.(a) Define conductivity of a solution of an electrolyte and state the relationship between conductance and conductivity of a solution. 2

(b) State Kohlrausch’s law of independent migration of ions. What is its importance ?

Q5.(a) How does the solubility of a gas change with decrease in temperature ? 1

(b) Define transference number. Give its relationship with ionic mobility. 2

(c) The molar ionic conductivity of Li* ions at 298 K is 3-87 x 10-3 S m? mol}. Calculate the ionic mobility of Li* ions.

Q6.(a) The cell reaction for a galvanic cell is given below : Ni (s) + 2Ag* (aq) ——> Ni?* (aq) + 2Ag (s)

(i) Write the half cell reactions at the anode and the cathode of the cell. 2

(ii) Calculate the value of standard cell emf. (Given EN 32 pyiis)= — 0:25 V and Eygt /Ag(s) = 0-80 V) 1

(iii) Predict whether the cell reaction given above is spontaneous or not. 1

(b) Define molality.

Q7.(a) Which one has greater Bunsen coefficient — CO, or O,? 1

(b) Give any two applications of electrolytic cells. 2

(c) Define concentration cells and give an example of an electrode concentration cell. 2 PARTB (Maximum marks : 25)

Q8.(a) How can you convert butanoic acid to N,N-dimethylbutanamide ? Also give the mechanism of this reaction. 14+3

(b) What are homopolysaccharides ?

Q9.Discuss the mechanism of Hofmann rearrangement.

Q10.What is a nitrosation reaction ? Write the nitrosation reactions and the products formed in them for the following : 5 Gi) Primary aliphatic amine Gi) Primary aromatic amine

(iii) Secondary aromatic amine

(iv) Tertiary aromatic amine

Q11.(a) How can you convert aniline to the following compounds ? 4 @ Phenol Gi) Chlorobenzene

(iii) Iodobenzene

(iv) Benzene

(b) What type of linkage connects the monosaccharides present in maltose ?

Q12.Discuss Merrifield Solid-Phase synthesis giving the sequence of the reactions involved.

Q13.(a) Briefly explain the primary, secondary, tertiary and quaternary structures of proteins. 4

(b) Name the products obtained by hydrolysis of (+) — sucrose.

Q14.(a) Illustrate using suitable reactions, how will you convert an aldohexose to an aldopentose using Ruff degradation. 4

(b) Name the monosaccharide units which are linked together in cellulose. 1 qe: BCHCT-135 6 dp _ AvapHl aT TA, V I AM 3:87x 10° S m? mol 12 | Lit SRT Ni (s) + 2Ag* (aq) ——> Ni?* (aq) + 2Ag (s) और Exot pags) = 0°80 v)