LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – CHEMISTRY
FIRST SEMESTER – April 2009
CH 1502 – ANALYTICAL CHEMISTRY
Date & Time: 20/04/2009 / 1:00 – 4:00 Dept. No. Max. : 100 Marks
Answer ALL the questions (10 x 2 = 20 marks)
- Mention the threshold limits of a vapour concentration of mercury, chromic acid, hydrogen sulphide and formaldehyde.
- 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?
- State any two conditions for a good fractionation.
- What is meant by partition chromatography?
- If 0.4 g of NaOH is dissolved in water to give 500 ml solution what will be molarity of the solution?
- Distinguish a primary standard from a secondary standard.
- Define ‘Concentration solubility product’.
- What are masking agents?
- What are the properties measured in TG and DTG methods?
- What do you understand by the term ‘reaction interval’ in thermal analysis?
PART – B
Answer any EIGHT questions (8 x 5 = 40 marks)
- Describe the calibration of a burette and a volumetric flask.
- List out any five advantages of using a standard glass joint apparatus.
- 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.
- Describe ‘hot filtration’ and give its significance.
- Outline the preparation and development of ‘plates’ for a TLC study.
- Explain, briefly, the various steps involved in recrystallization of a solid.
- What are metallochoromic indicators? Outline the principle and conditions for using such indicators.
- 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.
- Write an account of complexometric titrations.
- Find out the solubility of magnesium hydroxide in g L-1 if its solubility product is
1.20 x 10-11 at 25oC. (Mg = 24, O=16, H=1).
- Discuss the factors affecting solubility of precipitates.
- Sketch and account for the DTA analysis of calcium oxalatemonohydrate.
PART – C
Answer any FOUR questions (4 x 10 = 40 marks)
- Write a detailed account of various kinds of determinate and indeterminate errors in analysis.
- Discuss the principle, experimental technique and applications of ion-exchange
- Write notes on: (i) reduced pressure distillation (ii) electron capture detector in GC.
- Discuss the theory of acid-base indicators with two examples.
- (i) Describe post precipitation. (ii) How is post precipitation different from coprecipitaion?
(iii) Mention any three requisites of a wash liquid.
- Discuss the factors that influence a thermogram.
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