BSc Chemistry SEM IV 2018 19 May 2018-19 CHEMISTRY PAPER III Question Paper - Mumbai University | munotes

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1. Q3 The use of log-table/ non-programmable calculator is allowed
2. Q4 Answers for the same question as far as possible should be written together
3. Q1 A) Select the correct option & complete the following sentences. (any Twelve) 12 marks
4. Q1 Centrifugation is a method of separation li) Liquid —liquid chromatography is based on lil) Production of liquid fuels 1S an industrial process which
   • iv) Electrophoresis is based on
   • v) The separation in TLC is because of of solute between the two
   • a) adsorption b) partition c) both adsorption and partition Vi) Separation factor in solvent extraction is the ratio of of two Vil) is used as primary reference electrode A voltaic cell is also known as 1x) Quinhydrone electrode works satisfactorily in the pH range of
   • a) b) 8 to 11 c) 11 to 14
5. Q10 Glass electrode is an example of electrode Xi) Reduction potential of saturated calomel electrode is The unit of specific conductance is
   • a) b) Scm c) cm The Guassian Curve is a XIV) For rejection of a result, the test used is XV) Method of averages is used for
   • a) rejection of b) test of significance c) obtaining best fitting line XVi) The 4.0 d rule is used for
   • a) rejection of result b) test of significance c) for comparison of means
   • xvii) | Confidence limits are defined as xvili) In the expression for confidence limit R denotes
   • B) State True or False (any Three) 3
6. Q1 Solvent extraction is based on Plate theory li) Crystallization is a physical method based on solubility lil) pH meter can be used for soil analysis
   • iv) Potentiometric titrations involve construction of an electrolytic cell
   • v) F-test is also known as variance ratio test Vi) A test rejected by 2.5 d rule can be retained by 4.0 d rule
   • C) Match the column (any Five) Attempt the following (any Four) (20) A What is the principle involved in separation based on Thin layer Chromatography? Write various steps involved in this technique B List the important applications of TLC C Explain with respect to paper chromatography : i) Ascending technique 5
   • ii) Two dimensional technique of development of chromatogram D Explain in brief, the various steps involved in paper chromatography E Multi-step extractions with smaller volumes of extractant are more efficient than single step extractions using entire volume of extracting solvent. Explain F The distribution ratio D for a solute between an organic solvent and water in favour of organic. solvent. Calculate the percentage extraction if the two extractions are carried out with the volume ratio of 1 and 10
7. Q3 Attempt any Four A Describe the experimental procedure for carrying out potentiometric titration B Discuss the methods of determination of equivalence point from the following curves 20 marks
   • a) Volume of titrant b) AE/AV vs Volume of titrant C Discuss the pH metric titration curves obtained when a weak acid is neutralized by a D Write the important applications of pH measurement in biological and environmental E Discuss the conductometric titration curve in the neutralization of strong acid against a F List the advantages and limitations of conductometric titrations
8. Q4 Attempt any Four A Give the equation for the Gaussian distribution curve. Write the salient features of this B What is Null hypothesis? Outline a procedure for the application of null hypothesis to C Describe the method of least square for obtaining the best fitting line D The results for estimation of mercury in.a water sample for 10 replicate measurements are given below: Calculate the confidence interval for the mean at 95% level (Given: t= 2.26 for 95% confidence level) E The Eight different replicate analysis of a steel sample for cobalt content are given F Using the method of averages, obtain the best fitting standard line of the type y=mx+c for the following spectrophotometric analysis 20 marks
9. Q5 Attempt any Four A Discuss the principle of electrophoresis. List its important applications B Describe the continuous extraction technique of solvent extraction when the organic solvent is lighter than the water C Explain the term “indicator electrode”. Describe the construction and working of D List the advantages and limitations of glass electrode E Two sets of observations are represented below for the analysis of magnesium content in two samples: If the standard deviation is 0.021, determine whether the two means differ statistically or only numerically F In a chemical analysis of a sample of arsenic, the following results were obtained ppm of As 4.3,4.5,4.5, 4.6, 4.7, 5.0, Decide on the basis of 2.5 d and 4.0 whether the last measurement can be rejected 20 marks

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