BSc Chemistry SEM V 2019 20 Oct 2019-20 CHEMISTRY ANALYTICAL CHEMISTRY Question Paper - Mumbai University | munotes

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1. Q3 Use of log table/non-programmable calculators is allowed
2. Q1 any four of the following: 20 marks
   • A) Discuss the various grades of laboratory reagents
   • B) Calculate the molarity and molality of 69.8% (w/w) nitric acid solution [Given: molecular weight of nitric acid =63 and density of nitric acid solution =1.42 ]
   • C) Discuss the importance of quality concepts in industry
   • D) Calculate the percentage composition of each element present in urea [Given: atomic weight of: H=1.008, N= 14.007, O= 15.999 and C= 12.011]
   • E) Discuss the different equipments for the sampling of compact solids
   • F) Write a note on: ‘Preservation and dissolution of the sample’ any four of the following: 20
   • A) What are redox indicators? Discuss the use of diphenylamine as a redox indicator mentioning the role of acid mixture
   • B) 10.0cm? of 0.2M Fe (II) solution is titrated with 0.2M at pH 2 in acidic medium. Calculate the potential:
   • a)at half the equivalence point b)at the equivalence point
   • c) after addition of double the volume of titrant required at the equivalence point Comment on the nature of the titration curve
   • C) Discuss the theory of redox indicators
   • D) Calculate the values of pMg when: a)0.0cm? b)5.0 cm? c)10.0cm? and
   • d)11.0 0.01. M EDTA is added to.a 10.0 of 0.01 M Mg”* buffered to a constant pH of 10.0 Draw the nature of titration curve (pMg versus volume of EDTA) [Given: Kmy = 4.9 X 108 and a4 for EDTA at pH of 10.0
   • E) Discuss the use of EDTA as titrant. Write any three advantages of EDTA as a titrant
   • F) What are the different methods to increase selectivity in EDTA titrations? Discuss any two of them in brief four of the following: 20
   • A) Discuss the principle of flame photometric analysis
   • B) With the help of a neat diagram explain an electrothermal atomizer
   • C) Give any three applications and two limitations of AAS
   • D) Derive a mathematical relationship between the intensity of fluorescent radiation and the concentration of the solution
   • E) What is phosphorimetry? What are the factors affecting fluorescence and
   • F) Explain why sample solutions for nephelometry and turbidimetry have to be prepared very carefully. Draw a neat labelled diagram of a nephelometer
3. Q4 any four of the following: 20 marks
   • A) What are the factors affecting solvent extraction? Explain any one
   • B) What is solid phase extraction? Give any three applications
   • C) What are the requirements for high pressure pump used in HPLC? Name any two
   • D) Draw a neat labelled diagram of a typical HPLC unit and explain the function of degasser and precolumn
   • E) Mention the different detectors HPTLC and explain any one
   • F) What are the advantages and limitations of HPTLC?
4. Q5 A) Answer any five of the following 5 marks
   • a) What are certified reference materials?
   • b) What is the normality of 0.01Msulphuric acid? Name any one concentration unit independent of temperature
   • d) What is the condition in which the molarity and formality of the solution will be same?
   • e) Mention any one difficulty encountered in the sampling of gases
   • f) What is ambient sampling?
   • g) Name the equipment used for sampling of flowing liquids
   • h) Define: “Bulk ratio’ with respect to sample size
   • B) Select the correct option and complete the following statements: (any five) 05
   • a) During the direct EDTA added to metal ion solution to prevent precipitation of hydroxides of metal ion
   • b) The transition potential of ferroin V in IM During the titration of against the potential of indicator electrode before the equivalence point depends on the ratio of
   • i) il) ili)
   • d) EDTA is standardized using standard solution of
   • e) Of the following, is estimated by indirect EDTA titrations only
   • i) ii) iii)
   • f) Eriochrome Black T indicator exhibits colour between pH of 7
   • g) Ferroin indicator is a complex of with with Fe(II)
   • C) State whether true or false: (any five) 05
   • a) Nitrogen is used as an inert gas in hollow cathode lamp
   • b) Flame photometry gives the information of the molecular condition of the sample Flame photometry cannot be used for analysis of non-radiating elements
   • d) Turbidimetry is used to measure the amount of growth of a test bacteria in a liquid
   • e) Fluorescence is delayed phosphorescence
   • f) Phosphorescence of a solution is generally observed at liquid nitrogen temperature
   • g) For molecular weight determination by turbidimetry, a plot of turbidance versus concentration is plotted
   • h) In nephelometric analysis, highly monochromatic radiation is not necessary
   • D) Select the correct option and complete the following statements: (any five) 05
   • a) When the separation factor for the two solutes are very close, extraction method is used
   • b) Partition coefficient is equal to if the molecular state of the solute If the values of two metals are , excellent separation is achieved by
   • d) Due to different of the solutes in between the two liquid phases, separation of the solutes occur in HPLC
   • e) In HPLC, the at which the peak occurs on the chromatogram is characteristic of the analyte
   • f) detector used in HPLC is highly temperature sensitive
   • g) The method of sample injection in HPLC is reliable with respect to

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