B.Sc. (Biochemistry) Sem III 2018 2019 2019 ATKT Biochem Chemistry III Question Paper - Mumbai University | munotes

Questions asked in this paper

1. Q1 Separation of metal ions a. Separation of proteins
2. Q2 Electrophoresis b. Testing of significance
   • f. Separation of uncharged species
3. Q2 A. (i) Explain the term retardation factor. Give the significance for the qualitative analysis carried out in thin layer chromatography 5 marks
   • (ii) Give an account of physical methods of separation. 3
   • A. (i) Compare and contrast Thin Layer (TLC) and Paper Chromatography?
   • (ii) What is the difference between partition coefficient and distribution ratio? 3
   • B. (i) 100 cm? of an aqueous solution containing 1.2 g of solute is extracted three times with 20 portions of an organic solvent. The distribution ratio in favour of organic phase is 60. Calculate the amount of solute remaining un-extracted at the end of third extraction 5
   • (ii) Whatis Rp value? How is it useful for separation? 3
   • B. (i) the minimum value of the distribution ratio D which would allow 99.7% extraction of solute from 50 cm? of an aqueous solution with four successive 30 cm portions of ether? 5
   • (ii) Explain the classification of chromatographic methods on the basis of the stationery and mobile phase 3
   • C. (i) What are the different types of detectors used in HPLC? Discuss any one of it in detail. (4)
   • (ii) What are the factors that affect the extraction in solvent extraction process? 4
4. Q3 A. (i) What is indicator electrode? Which are the electrodes that canbe indicator electrodes in acid base titrations?
   • (ii) What are the advantages of conductometric titrations? 3
   • A. (i) Explain the basic principle of conductometric measurements. Explain the construction of conductivity cell 5
   • (ii) What are the applications of potentiometric titrations? 3
   • B. (i) Explain the nature of the curve for the titration of (i) strong acid against strong base and (ii) weak acid against weak base conductometrically 5
   • (ii) What is a pH meter? Explain any two types of pH meters. 3
   • B. (i) What is a quinhydrone electrode? Derive an expression between and — pH using quinhydrone in acidic medium 5
   • (ii) With the help of a diagram discuss the construction of combined pH electrode
   • C. (i) Explain the principle of potentiometric titrations. 4
   • (ii) Discuss the applications of pH metry in biological and environmental 4
5. Q4 A. (i) The pH of a solution was determined with following results Calculate the standard deviation and variance 5 marks
   • (ii) Explain 2.5 d rule and 4 d rule for the rejection of doubtful data. 3
   • A. (i) What is Gaussian distribution curve? Describe salient features of this curve? 5
   • (ii) Calculate the mean and median for the following sets of values: 3
   • B. (i) For the data in the following table, derive an equation of the type y=mx+c by the method of least square 5
   • (ii) Explain Null hypothesis. 3
   • B. (i) Explain different methods used to describe a precision of ameasurement
   • (ii) In the analysis of sulphur content of a sample, the following values were Find whether the value 0.50 can be retained on the basis of the Q-test 3
   • c. A large number of measurements for the estimation of traces of titantumin several samples from the same source, gave a standard deviation of 0.1 ppm of titanium. If a single measurement of a particular sample gave 7.85 ppm titanium. Calculate the true mean with 95% confidence limit (Z for 95% confidence limit = + 1.96) 4
   • C. Define: a) The true value of ameasurement Median 4
   • c) Number of degree of freedom
6. Q5 Answer any four of the following. 20 marks
   • A. A 150 cm’ of aqueous solution containing of iodine is equilibrated with 100 of carbon tetrachloride. The distribution coefficient between carbon tetrachloride and water at room temperature is 75 in favour of carbon tetrachloride. Calculate the weight of iodine remaining un-extracted in the
   • (i) two extractions with 50 cm? of
   • (ii) four extractions with 25 cm? of CCla
   • B. Discuss the applications of thin layer chromatography?
   • C. Discuss advantages and limitation of potentiometric titrations
   • D. Explain the various graphical methods used to determine the equivalence point in potentiometric titrations
   • E. Describe the method of least square for obtaining the best fitting line
   • F. For the data in the following table, derive an equation of the type y = mx by using the method of averages:

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