BSc Chemistry SEM III ATKT 2017-18 ATKT Chemistry Paper III Question Paper - Mumbai University | munotes

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1. Q2 Figures to right indicate full marks
2. Q3 Use of log table and non-programmable calculators is allowed
3. Q1 A Select the correct option & complete the following sentences (12 M)
4. Q1 In semi-micro analysis the sample size
   • a) more than100 mg _ b) between 10 mg to c) between 10 mg
5. Q2 Analysis of impurities in the given sample is ---------- analysis
6. Q3 Sample is miniature replica of
7. Q4 Physical limitations of the analyst and biased approach of the analyst introduce
8. Q5 The concentration of 1 M solution is equal to the concentration of --------- solution
9. Q6 Determinate errors are also ----- errors
10. Q7 In the titration of weak acid against strong pH at equivalence point is
    • a) Greater than than 7 equal to 7
11. Q8 Sintered glass crucible is used in -------------- analysis
    • a) titrimetric b) gravimetric c) titrimetric as well as gravimetric
12. Q9 For dilute solution of species, the graph of absorbance of it’s solution against
    • b) Straight line with positive slope making Y intercept
    • c) Straight line with negative slope making Y intercept
13. Q10 Absorbance of ---------- solution can be measured by using colorimeter Only colored b) Only colorless c) Colored as colorless
14. Q11 In titration, absorbance of titrated solution during titration is plotted against volume of titrant added
    • a) Conductometric b) redox 12). Amax. of an absorbing species is
    • a). the maximum wavelength available
    • b) wavelength at which absorbing species shows maximum absorbance
    • c) wavelength at which absorbing species shows maximum transmittance
    • B. State whether the following statements are true or false: 3
    • i) Conductometry.is non-classical method of analysis
    • ii) A multistep washings with small volume of wash liquid are more efficient to remove the impurities single step washing with large volume of wash liquid
    • iii) A violet beam of wavelength 395 nm is a polychromatic light
    • Q. P. Code: 19826
    • C) Match the following columns (5M) phenolphthalein indicator ld Sampling of air
15. Q2 Ai) How are determinate errors minimized? (5M)
    • ii) Distinguish between accuracy and precision. (3M) A i) Explain the terms random and systematic sampling. (5M)
    • ii) Explain coning and quartering method used for reduction of sample size in (3M) B i) An acid buffer of pH 5.60 was prepared. Its pH was measured thrice. The readings obtained were 5.58, 5.61 and 5.59. Calculate absolute error and percentage relative error for these readings. (5 M)
    • ii) Distinguish between constant error and proportionate error? (3 M) B i) In gravimetric estimation of barium as the following results were obtained (5M) Weight of sample |. Weight of barium obtained | Weight of barium actually present For this estimation, calculate the absolute error and the relative error in parts per thousand
    • ii) Distinguish between determinate error and indeterminate error? (3 M) Define a) Complete analysis b) Sampling (2M)
    • ii) Define a) Analytical chemistry b) Increment (2M)
    • C) i) Define a) Proximate analysis b) Sampling techniques (2M)
    • ii) Define a) Classical method of analysis b) Sampling unit (2M)
16. Q3 Ai) What are the requirements a reaction must fulfill to be studied by titrimetric
    • ii) What is iodometry and iodimetry? (3 M)
    • Q. P. Code: 19826 A i) Explain the different steps involved in a precipitation gravimetry
    • ii) What are the applications of gravimetric analysis? (3M)
    • B. i) Calculate the amount of solute required to prepare 700 cm? of 0.05 N succinic acid and Il. 500 cm? of 0.05 N Sodium hydroxide (NaOH)
    • ii) What are the conditions of precipitation? (3 M)
    • B. i) Consider the titration of 10 cm? of 0.1 M ammonium hydroxide (Kp = 1.8 X ) with 0.1 M HCI. Calculate pH of the solution i) at the start of titration ii) when 5.0 cm? of 0.1 M HCI has been added. (5M)
    • ii) What is volatilization gravimetry? (3M)
    • C) i) Define a) Titration curve b) Standard solution (2M)
    • ii) Define a) Ignition of a precipitate. b) Precipitation gravimetry (2 M)
    • C) i) Define a) Neutralization reaction b) Titration error (2M)
    • ii) Definea) Drying of b) Titrimetric analysis (2 M)
17. Q4 Ai) What are the deviations from Beer-Lambert’s law. (5M)
    • ii) What is absorption and emission spectroscopy? (3 M) Ai) Draw schematic diagram of single beam colorimeter. Describe the function of each
    • ii) the applications of UV- Visible spectroscopy? (3M)
    • B. i) A solution of a substance with molar absorptivity 10500 dm? mol? gives an absorbance 0.70 having a path length 1 cm. Calculate concentration and % transmittance of the solution. (5M)
    • ii) What are the advantages of photometric titrations? (3M)
    • B. i) M solution of a substance has 50% transmittance at Amax = 280nm when a cell of path length 1 cm is used. Calculate the molar absorptivity of the substance. (5M)
    • ii) Distinguish between colorimeter and spectrophotometer. (3M)
    • C) i) Define a) Absorbance b) Radiant power (2M)
    • ii) Define a) Transmittance b) Molar absorptivity (2M)
    • C) i) Define a) Detector b) Analyte (2M)
    • Q. P. Code: 19826
18. Q5 Answer any four questions from following : (20 M)
    • A) Write a note on sampling of immiscible liquids
    • B) Explain types of classical and non-classical methods of analysis
    • C) Explain the methods used to determine end point of neutralization titrations?
    • D) Explain digestion of precipitate and its importance in gravimetric analysis
    • E) The absorbance of a 1 x x M solution placed in a cell with path length was found to be same as another solution of same substance placed in with path length using the same incident radiation. Calculate the concentration of second solution
    • F) With the help of a neat labeled diagram explain the working of photomultiplier tube used as detector in colorimeter and spectrophotometer

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