BSc Chemistry SEM III ATKT CHEMISTRY PAPER III Question Paper - Mumbai University | munotes

Questions asked in this paper

1. Q1 All questions are compulsory
2. Q2 Figures to right indicate full marks
3. Q3 Use of log table and non-programmable calculator is allowed
4. Q1 A] Fill in the blanks with suitable options and rewrite the statement
5. Q1 Titration error is type of error
   • ii) Semi micro analysis refers to analysis in which sample size is $
   • a) more than 100 mg. b) less than 10 10mg to 100 mg
   • iii) Random sampling is
   • iv) Analysis sample is prepared from
   • v) Precision is measured in terms of
   • vi) Uncertainty of last digit of measurement is an example of type of error
   • vii) Which of the following is used as a primary standard in Redox titration? The plot of pH against volume of titrant added is known as
   • ix) Solution taken in flask for titration is called as
   • x) In complxometric titration, generally of the following is used as a titrant x1) Nickel can be precipitated as Ni-DMG in medium x11) Ostwald’s ripening refers to of precipitate
   • xiii) Which of the following is optical type of instrument? x1v) Beer’s law spells about relationship between Absorbance and
   • a) transmittance b) concentration of solution c) thickness of solution
   • xv) Photomultiplier tube is used as a in optical instruments like photometer,
   • xvi) Absorbance of solutions can be measured by uv-visibal spectrophotometer
   • xvii) Wavelength region of uv is xviii) Unit of absorbance is
   • a) none of these
6. Q1 B] State True or False (Any Three) 3 marks
7. Q1 Incomplete drying of precipitate is methodic type of error
   • ii) Determination of the elements present in the sample, irrespective of chemical form in which they are present is called as proximate analysis Diphenyl amine is used as an indicator in acid base titration
   • iv) Digestion of precipitate helps to give particles of uniform size
   • v) In spectrophotometer, monochromater used is a colour filter
   • vi) Extension in conjugation in carbon chain is always associated with shift towards longer
8. Q1 C] Match the following: (Any Five) 5 marks
9. Q2 Solve any four of the following 20 marks
   • a) Give comparative account on accuracy and precision
   • b) State and explain the terms 1) Increment ii) Sampling unit 1ii) Macro analysis iv) Micro
   • c) What is the purpose of sampling? Describe methods of sampling of different types solids
   • d) Enlist the classical methods of analysis. Write advantages of it. Discuss any one classical
   • e) Three samples of alloy were analyzed for tin content, following results were obtained The actual Tin content in each sample is 80% of the mass of respective sample, Calculate absolute error, relative error, relative error in pph, also comment on the result
   • f) of blood was analysed for Hb content. Calculate absolute error, relative error, relative error in pph and relative error in ppt If the actual Hb content is 15.07 Solve any four of the following 20
   • a) What are secondary standards? What conditions must they satisfy? Give examples of secondary standards used in acid base, and redox titration
   • b) Discuss estimation of Ni in Cu-Ni alloy
   • c) Explain the methods of calibration of burette and pipette
   • d) 10cm? 0.1M ammonium hydroxide is titrated against 0.1M HCI solution at 298K. Calculate pH at equivalence point (Given Kb for ammonium hydroxide = 1.8 x Kw =
   • e) Describe the difference with example between 1) end point and equivalence point
   • ii) One colour indicator and two colour indicator
   • f) Discuss unit operations of gravimetric analysis 1) Digestion ii) Washing
10. Q4 Solve any four of the following 20 marks
    • a) With the help of neat and labeled diagram explain the construction and working of double
    • b) Compare: photometer and spectrophotometer
    • c) State Lambert’s law and derive its mathematical equation
    • d) With the help diagram describe construction and functioning of “photo emissive cell’
    • e) The absorbance of a 3.2 x 107M solution when placed in a cell of length 2cm was found to be 0.456 at 650nm, Calculate molar absorptivity. If the same solution is placed in cell of length 4cm calculate 1) absorbance ii) transmittance and ili) % transmittance
    • f) The absorbance of a 2.8 x solution was found to be 0.202 at 420nm when placed in cell of length 2cm. Calculate the absorbance of solution having concentration 1) double of original concentration 11) half of original concentration and both are placed in cell of length Solve any four of the following 20
    • a) Describe method of sampling of flowing liquid
    • b) How minimization of determinate errors can be carried out?
    • c) Describe 1) Complexometric titration
    • d) Explain the effect of 1) common ion effect on the solubility of precipitate
    • e) With the help of neat and labeled diagram explain the construction and working of single
    • f) Write advantages and limitations of photometric titrations

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