BSc Chemistry SEM V 2016 17 2016-17 Analytical Chemistry (Old) Question Paper - Mumbai University | munotes

Questions asked in this paper

1. Q1 All questions are compulsory
2. Q2 Figures to the right indicate full marks Use of logtables/non-programmable calculator is allowed
3. Q1 Answer any three of the following: 15 marks
   • A) the sourcewise classification of determinate errors. Explain each class with suitable examples
   • B) In replicate analysis of Ni alloy, the following results were obtained 1% of Ni metal | 55.14
   • C) Explain the method of collecting representative sample of flowing liquid with a neat labelled diagram
   • D) determinatin of calcium from sample containing 400 mg of calcium by a method, following results were obtained Find i) absolute error ii) relative error iii) relative error in ppt BE) Define the terms ‘sample’. Explain the use of coning and quartering method in the sampling of solids
   • F) Discuss the use of sample thief in the sampling of heterogeneous liquids
4. Q2 Answer any three of the following?
   • A) the nature of titration curve in the titration of weak acid versus strong base, explaining the choice of indicators the Mohr’s method of determining the end point in argentimetric titrations. Explain its limitations
   • C) the nature of titration curve in the titration of strong acid versus strong base, justifying the suitable indicators
   • D) Distinguish between spectrophotometers and colorimeters
   • E) diagram of single beam spectrophotometer and give the function of its components
   • F) Explain the use of adsorption in indicators in precipitation titrations with suitable example
5. Q3 Answer any three of the following: extraction method for extractant: heavier than water w.r.t. solvent extraction six percent solute is extracted from 100cm? of aqueous solution by extraction with two 0.05 dm? of organic solvent. What is distribution ratio of solute in favour of organic solvent 15 marks
   • C) principle and any three applications of TLC
   • D) cm of 0.5M aqueous solution of Fe** is to be extracted with 10cm? of ether. Calculate how many extractions are necessary so as to bring the concentration of Fe** in the solution to Given: D 17-6
   • E) What are the advantages of TLC over paper chromatography?
   • F) Explain the following w.r.t. paper chromatography
   • (i) Application of sample (ii) Location of separated components
6. Q4 Answer any three of the following: 15 marks
   • A) With the help of a neat labelled diagram, describe the construction and working of an electrothermal atomizer used in AAS
   • B) Give any five application of AAS
   • C) the various factors affecting fluorescence
   • D) Discuss the principle of flame photometry
   • E) a neat labelled diagram of turbidimeter and explain its use in determining concentration of sample solution
   • F). (i) turbidimetric titrations
   • (ii) determination of molecular weight by turbidimetry
7. Q5 A) Fill in the blanks. 4 marks
   • a) The median of the set of values, 21.31, 21.27, 21.33 and 21.29=
   • b) Most commonly used acid for dissolving silicate rocks is
   • c) The most frequently occuring data from the given set of observations is called
   • d) The sample prepared by mixing the increments is
   • A) State true or false. 04 Blank determination is one of the methods to minimise Precision denotes the closeness of a measurement to its accepted
   • r) In systematic sampling, sample units are drawn, in a definite sequence at equal intervals from one another
   • S) Standard deviation ‘s’ of the percentage impurity due to sampling is given by s
8. Q5 B) Fill in the blanks. 4 marks
   • a) Bromocresol green can be used as preferred indicator in the titration of weak base against _ acid
   • b) In the titration of weak acid against weak base, pH before the equivalence point can be calculated by equation,
   • c) In Volhard’s method, used as a coagulant to prevent the reaction between thiocyanate and AgCl
   • d) Calibration curve is a plot of ___ versus concentration in UV - visible spectroscopy
9. Q5 B. State true or 4 marks
   • p) It is advisable to avoid the use of simple indicators to detect the equivalence point in weak acid-weak base titration
   • q) Volhard’s method for the determination of halides is a direct
   • r) In UV - visible spectroscopy, multiplication factor can be used to determine the concentration of the solution
   • s) Unsaturated organic compounds absorb in the visible region
10. Q5 C) in the blanks. 4 marks
    • a) Bush-Densen equation is given by
    • b) If = 0.01 in a given solvent extraction, then D
    • c) values can be used to identify the components of mixture in TLC In TLC, an adsorbent coated ona glass
    • C) true or false
    • P) In solvent extraction, role of solvent is to neutralise the charge of the metal ion 7 q) Separation factor is the ratio of square of distribution ratios of the two solutes
    • r) Paper chromatography is a type of column chromatography
    • s) R, factor for a particular solute depends on nature of mobile phase in the blanks: 03
    • a) Fluorescent intensity is directly proportional to of
    • b) The phosphoriscope measures in the presence of The role of in AAS is to eliminate radiations emitted by the flame
11. Q5 D) true or false. 3 marks
    • p) Phosphorescence experiments are carried out at higher Phospherescence spectrum always occurs at longer wavelength than fluorescence spectrum In flame photometry, intensity of emitted radiations remains unaffected by the presence of acid in the sample solution

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