LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

WD 02

FIRST SEMESTER – April 2009

CH 1502 – ANALYTICAL CHEMISTRY

 

 

 

Date & Time: 20/04/2009 / 1:00 – 4:00       Dept. No.                                                       Max. : 100 Marks

 

 

PART –A

Answer ALL the questions                                                                            (10 x 2 = 20 marks)

1. Mention the threshold limits of a vapour concentration of mercury, chromic acid, hydrogen sulphide and formaldehyde.
2. Repeated estimation of the percentage of carbon in a certain organic compound yielded the result, 38.42, 38.02 and 38.22 in three trials. What is the ‘spread’ of the above set of data?
3. State any two conditions for a good fractionation.
4. What is meant by partition chromatography?
5. If 0.4 g of NaOH is dissolved in water to give 500 ml solution what will be molarity of the solution?
6. Distinguish a primary standard from a secondary standard.
7. Define ‘Concentration solubility product’.
8. What are masking agents?
9. What are the properties measured in TG and DTG methods?
10. What do you understand by the term ‘reaction interval’ in thermal analysis?

PART – B

Answer any EIGHT questions                                                                 (8 x 5 = 40 marks)

11. Describe the calibration of a burette and a volumetric flask.
12. List out any five advantages of using a standard glass joint apparatus.
13. Assess the average deviation from the ‘mean’ and also from the ‘median’ of the percentage of chloride obtained in three trials, namely, 24.39, 24.19 and 24.36.
14. Describe ‘hot filtration’ and give its significance.
15. Outline the preparation and development of ‘plates’ for a TLC study.
16. Explain, briefly, the various steps involved in recrystallization of a solid.
17. What are metallochoromic indicators? Outline the principle and conditions for using such indicators.
18. Calculate the pH of the solution obtained by mixing 5.0 g of acetic acid and 7.5 g of sodium acetate and making the volume equal to 500 mL. Given: the dissociation constant of acetic acid is 1.75 x 10^-5 at 298 K.
19. Write an account of complexometric titrations.
20. Find out the solubility of magnesium hydroxide in g L^-1 if its solubility product is

1.20 x 10^-11 at 25^oC.  (Mg = 24, O=16, H=1).

21. Discuss the factors affecting solubility of precipitates.
22. Sketch and account for the DTA analysis of calcium oxalatemonohydrate.

 

PART – C

Answer any FOUR questions                                                                  (4 x 10 = 40 marks)

 

23. Write a detailed account of various kinds of determinate and indeterminate errors in analysis.
24. Discuss the principle, experimental technique and applications of ion-exchange

chromatography.

25. Write notes on: (i) reduced pressure distillation (ii) electron capture detector in GC.
26. Discuss the theory of acid-base indicators with two examples.
27. (i) Describe post precipitation. (ii) How is post precipitation different from coprecipitaion?

(iii) Mention any three requisites of a wash liquid.

28. Discuss the factors that influence a thermogram.

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

WD 18

FIFTH SEMESTER – April 2009

CH 5501 – ANALYTICAL CHEMISTRY

 

 

 

Date & Time: 17/04/2009 / 9:00 – 12:00 Dept. No.                                                  Max. : 100 Marks

 

 

 

PART – A

 

Answer ALL the questions                                                                                        (10 x 2 = 20 marks)

1. Define relative error.
2. How is antidote prepared?
3. Why is vaccum distillation needed for some liquids?
4. Define elution and eluant in chromatography.
5. Mention any two characteristics of a primary standard substance.
6. Define molarity
7. Differentiate equivalence point from end point.
8. How is solubility of sparingly soluble salt related to solubility product for AgCl?
9. State Beer-Lamberts law.
10. Draw the possible modes of vibrations for water molecule.

PART – B

Answer any EIGHT questions                                                                              (8×5=40 marks)

 

11. Define absolute error. The accepted value for the sets of data 25.40, 25.36, 25.26, 25.34 is 25.28.  Calculate the absolute error.
12. Write a note on Soxhlet extraction.
13. What are the steps involved in separation of mixture of components using TLC technique.
14. Mention principle and the different types of chromatography.
15. What are the different types of titrimetric analysis? Explain them with examples.
16. 20ml 0.1M CH COOH is titrated with 0.1 M NaOH calculate the pH at the equivalence point (Ka = 1.8 X 10^-5).
17. What is metal ion indicator? Give examples.
18. Explain co-precipitation and post precipitation with examples.
19. What is an adsorption indicator? Explain with an example.
20. Differentiate chromophore and auxochrome.
21. How is Beer-Lambert’s law veified? Explain them.
22. What are the factors affecting the absorption maximum in UV-visible spectroscopy?

 

PART – C

Answer any FOUR questions                                                                                  (4 x 10= 40 marks)

 

23. a) Define Mean, Median and Standard deviation                   (6)
24. b) Find out the mean and median for following data: 48.32, 48.36, 48.23, 48.11 and 48.38. (4)
25. a) Compare the following: distillation, fractional distillation and vaccum distillation.  Under

what conditions the above techniques are adopted for purification.                                         (7)

 

1. b) For a given volume of solvent, multiple extraction is more efficient than single extraction.

Why?                                                                                                                                              (3)

 

25. a) Explain the separation of a mixture by Gas chromatography.                    (7)
26. b) Write the different types of ion exchange resin used in ion-exchange chromatography.          (3)

 

26. a) What is meant by chelating agent? Give examples.                                                                  (2)
27. b) Explain the different types of EDTA titrations                                                                       (8)

 

27. a) How is silver ion determined by Volhard method?        (5)
28. b) Explain the factors affecting the solubility of a sparingly soluble salt.                                      (5)

 

28. Draw the block diagram of IR spectrometer and explain them. How IR absorption bands useful

in the identification of organic compounds?  Give examples.

 

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