BSc Chemistry SEM V 2017 18 2017-18 ANALYTICAL CHEMISTRY 18 PAPER IV Question Paper - Mumbai University | munotes

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1. Q3 Use of log table/ non-programmable calculator is allowed Answer any three of the following. 15
   • A) Discuss the interference of dissolved oxygen, with reaction involved in polarographic analysis, explaining its removal
   • B) In polarographic determination, a series of standard solutions. and an unknown solution containing cadmium ions were prepared and the wave heights were determined. The results were as follows Calculate the concentration of the unknown solution
   • C) Mention any five advantages of DME over other micro electrodes
   • D) In polarographic estimation of Cu?* ions, the following results were obtained ig= 5.65 D= 6.85 x 10cm? m= 3.45 and t= 2.9s. Calculate the concentration of Cu** ions in the sample solution
   • E) Give any five applications of amperometric titrations
   • F) Explain the nature of ampemetric titration curve when titrand and titrant both are reducible,
2. Q2 Attempt any three of the following. 15 marks
   • A) What is the role of detector in GC? Explain flame ionization detector with help of a labelled
   • B) Explain the following with respect to GC:
   • (a) HETP, and Eddy diffusion
   • C) neat labelled diagram of HPLC and explain the isocratic and gradient elution
   • D) Give any five applications of HPLC
   • E) What is ion-exchange capacity of ion exchange resin? How is it determined for a cation
   • F) are the requirements of an ideal ion-exchange resin?
   • Q.P. Code :04765
3. Q3 Answer any three of the following 15 marks
   • A) What is normal error curve? Describe its salient features
   • B) Five replicate measurements for the determination of iron of iron gave the 15.61, 15.52, 15.63, 15.58, and 15.64% iron Calculate the 95% confidence interval for mean if no additional information about the precision of the method is known Given : t = 2.78, for 95% confidence limit
   • C) The following table gives dependence of y on x Assuming a linear relationship between the variables, obtain an equation of the type y=mx, using the method of averages
   • D) What are different methods used to increase the selectivity of EDTA in EDTA titration ?Discuss any two of these in brief
   • E) Explain the following w.r.t. EDTA titrations
   • i) Direct titrations, and
   • F) Discuss the theory of redox indicators, explaining the basis of selection of an indicator in redox
4. Q4 Answer any three of the following: 15 marks
   • A) Explain the term quality control and quality assurance
   • B) Explain the term: i)GLP, and
   • ii) ISO
   • C) Discuss the basic principle of mass spectrometry
   • D) Draw the schematic diagram of the TGA set up. Give any three requirements of a good
   • E) What is a thermogram? Discuss the nature of thermogravimetric curve obtained in the thermal decomposition of CuSO4.5H20
   • F) What are the applications of NAA?
   • Q.P. Code :04765
5. Q5 A) Fillin the blanks 4 marks
   • b) In DME when the mercury drop gets detached, the current becomes
   • c) In polagraphy, the electrode of large surface area which retains its own potential is
   • d) Triton X-100 is used for suppressing the polarographic
   • B) State true or false. 04
   • p) The concentration of supporting electrolyte should be at least 100 times less than the
   • q) Diffusion current depends on temperature
   • r) In polarography, conditions are so maintained that the movement of ions to DME is controlled by concentration gradient as well as potential gradient
   • s) Residual current in polarography is regarded as non-faradic current
6. Q5 Fillin the blanks 4 marks
   • a) As the number of theoretical plates in the GC column increases, the efficiency of the
   • b) The measure of separation between adjacent peaks in a GC chromatogram is
   • c) In HPLC, precolumn prevents the stripping of the phase from the analytical
   • d) The equilibrium constant, obtained by applying Law of mass action to a reaction involving ion exchange equilibrium is called as
   • B) State true or false. 04
   • p) The carrier gas used in GC separations should not react with the sample
   • q) GC is used only for volatile and thermally stable compounds
   • r) Trace metal ions in sea water can be concentrated by ion-exchange chromatographic
   • s) Higher the concentration of ions in the solution lower is the exchange in ion exchange
   • Q.P. Code :04765
7. Q5 Fillin the blanks. 4 marks
   • b) Metal indicator complex should be slightly stable than metal EDTA complex in
   • c) In redox titration of Fe (II) Vs. diphenylamine is first irreversibly oxidized to
   • d) A redox titration curve is a plot of versus volume of titrant State true or false. 04
   • p) Redox titration involve transfer of electrons between reactant and titrant
   • q) 1,10 phenanthroline iron (II) sulphate is commonly known as ferroin indicator
   • r) Concentration of SO,” can be determined with the help of EDTA
   • s) EDTA titrations are always carried out in basic medium
8. Q5 the blanks 3 marks
   • a) In a mass spectrometer, a ions according to their masses
   • b) The decomposition temperature in TG increases with in particle size
   • c) In neutron activation analysis, stable nucleides are D State true or false 03
   • p) A high vaccum is required to be maintained in mass spectrometer
   • q) Multi-elemental analysis is possible by NAA
   • r) In thermogravimetic technique, it is necessary to avoid fast heating rate to detect

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