TYBSc Chemistry Sem 6 Analytical Chemistry Question Paper PDF 2026 - Mumbai University | munotes

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1. Q1 Attempt any four of the following:
   • A) Distinguish between : 5
   • a) polarizable electrode and non-polarizable electrode
   • b) voltammetry and polarography
   • B) Explain the need to remove dissolved oxygen from a solution before recording its 5
   • C) A Zn* ion solution of unknown concentration gave a diffusion current of 4.25 uA. When 5
   • 3.0 cm? of 0.01 mol dm * solution of ion was added to 25.0 cm? of unknown, the diffusion current increased to Calculate the concentration of in the sample
   • D) A0.878 mM Pb* ion solution gave a diffusion current of 7.75 mercury flow rate 5 and drop lifetime were 2.63 mgs"! and 2.88 s respectively. What is the diffusion coefficient of Pb*?
   • E) Give the advantages and limitations of amperometric titrations. 5
   • F) Explain: a) basic principle of amperometric titrations. 5
   • b) neat labelled diagram of the polarographic cell
2. Q2 Attempt any four of the following:
   • A) Mention the detectors used in GC. Describe the principle and construction of any one 5 detector with a neat labelled diagram
   • B). are the applications of gas chromatography? 5 Explain the terms w.r.t.GC: retention time, HETP and resolution. 5 Substances A and B gave retention time 15.15 and 16.60 min. respectively, on 5 column. An unretained species passed through the column in 1.30 min. The peak widths at base for A and B were 1.01 and 1.20 min. respectively. Calculate i) resolution number of theoretical plates iii) plate height
   • E) What is ion exchange capacity? How is cation exchange capacity of a resin 5
   • F) — Define selectivity coefficient for an ion exchange process. What are the factors affecting 5 Attempt any four of the following: A Discuss the use of chemicals as food preservatives. 5 B What is the role of chicory in coffee? Discuss the constituents present in coffee. 5 C Write the nutrients present in milk and discuss the analysis of milk for lactose by Lane 5 D Write the composition of tea and discuss the detection of any four adulterants present in it. 5 E Write the properties of antiperspirants and describe a gravimetric method to estimate 5 amount of zinc in antiperspirants F What are sensory properties of cosmetics? Describe a method to estimate amount of 5 magnesium present in face powder
3. Q4 Attempt any four of the following: A Draw a schematic diagram of TGA instrument and discuss any three of its components. 5 B Discuss the principle of DTA and explain the nature of DTA curve for dehydration of 5 C Discuss the factors that influence the TG curve. 5 D a) Compare the technique of TGA with DTA. 3
   • b) Write on: Reference material used DTA. 2 E Discuss the principle of thermometric titrations and explain its application in the titration 5 F Discuss the need for validation of a method and explain the significance of linearity, 5 selectivity and specificity w.r.t. method validation true or false (any five) 5
   • a) drop time can be changed by adjusting the height of the mercury reservoir in
   • b). In amperometric titrations, a “V’ shaped titration curve is obtained, when only the titrant is reducible species
   • c) Limiting current is the sum of diffusion current and residual current
   • d) Rotating platinum electrode is used for determination of halides by precipitation titration
   • e) The indifferent electrolyte present in large concentration in the polarographic analysis is known as the maxima suppressor Polarogram is a plot of current versus voltage
   • g) Due to continuous renewal of DME, simultaneous determination of several metals is
   • h) The rotating platinum electrode has the working range upto +0.4V versus SCE Select the correct option: (any five) 5
   • a) The contribution to band broadening due to different velocities of solute molecules across the band is known
   • b) For weakly basic anion exchangers, pH must. be
   • i)greater than 7 ii) less than 7 iii) 7
   • c) Cation exchange resin is a polymer containing groups.as an integral part of the
   • d) Sample port temperature in GC is kept at the boiling point of the
   • e) lon exchange chromatography can be used for ‘
   • 1) demineralisation of water ii) separation of amino both (i) and (ii)
   • f) Swelling of a resin is due to high proportion of groups
   • i)polar neutral true or false (any five) 5
   • a) Irradiation reduces the need of food preservatives Mannitol is used as an indicator for the determination of boric acid in food sample
   • c) The action of sodium salt of benzoic acid as preservative is pH dependent
   • d) Castrol oil is used in lipstick for the dissolution of dyes
   • e) Zinc oxide is added to face powder to give a covering power
   • f) Aluminium salts are used in antiperspirants to increase its fragrance
   • g) Sugar syrup is the adulterant added to honey
   • h) Amount of kaolin in face powder should not exceed 25% Select the correct correct option: (any five) 5
   • a) In the application of DTA, which of the following parameter is measured for glasses?
   • b) Which of the following thermal technique detects every physical or chemical change whether or not accompanied by change in weight?
   • c) Which of the following represents the loss of water of crystallisation in the TGA curve?
   • d) How many peaks are observed in the thermometric titration curve for the titration of mixture and against EDTA?
   • e) The formation of which of the following product shows an upward peak in the DTA curve of calcium oxalate monohydrate in the atmosphere of air?
   • f) How many endotherms are observed in the DTA curve of calcium oxalate monohydrate?
   • g) Which of the following term is used for expressing stability of a method against

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