BSc Chemistry SEM III 2022 2023 Oct 2023 CHEMISTRY III Question Paper - Mumbai University | munotes

Questions asked in this paper

• ii) Figures to the right indicate full marks

1. Q1 A. Multiple choice questions (any 12) (12M)
   • 1) Accuracy stands for
   • 2) Acid base titrations are based on the. reactions
   • 3) In ------------ silica is stationary phase and organic solvent is mobile phase
   • 4) A definite amount of sample drawn from each sampling unit is
   • 5) Blowing of a pipette is
   • 6) The value of the selectivity may vary from -----------?
   • a. Otol 1 d)2tol Indicators are used in complexometric titration
   • 8) . [s a suitable indicator for the titration of strong acid and weak alkali
   • 9) the most widely used chelating agent in complexometry
   • 10) In precipitation titration generally. is used as a titrant
   • 11) lodometry is one of the most important -------- titration method
   • 12). ------------ is not use as indicator in complexometry
   • a. Murex ide b. EBT c. phenol red d. all of these
   • 13) Visible spectrometry use radiation in the region of electromagnetic
   • 14) For analysis in UV region the cuvette should be made up of
   • 15) Filters are used as a monochromators in ;
   • 16) Spectrophotometers used as a monochromator
   • a) Filters b) grating C)both filters as well as grating d) photocell
   • 17) According to Beer — Lamberts law plot of absorbance versus concentration is a
   • a) straight line passing through origin with a positive slope
   • b)straight line passing through origin with a negative slope
   • c)straight line with a negative slope and intercept on x axis
   • d)straight line with a negative Slope and intercept on y axis
   • 18) in a visible spectrum light absorbed is blue then complementary colour transmitted is
   • a) red d) green
   • B. Match the following
   • 1. Colorimeter a. two different types of electrodes are used
   • 2. Photo cell b. potassium chloride against silver nitrate
   • C) Write true or false
   • 1. Solvent extraction is based on the principle of Nernst's distribution law
   • 2. Spectrophotometers are more sensitive than colorimeter
   • 3. Colloidal precipitate is easily filterable
2. Q2 Attempt any four: 20 marks
   • A. Define the following: i) Gross sampling ii) Sampling unit iii) Increment iv) subsample
   • B. What is titration? Write down the types of titration ? Explain any one type of titration?
   • C. What is the purpose of sampling? Describe the methods of sampling of immiscible and
   • D. What are the various factors to be considered while choosing an analytical method?
   • E. What is proximity analysis? Write the proximate analysis parameter
   • F. Calculate the absolute and relative error for the measurement, if in the determination of the chloride content of a water sample 100 cm3 required 1.8 cm3 of 0.1 M silver nitrate and the expected value of the chloride content is 70 ppm
3. Q3 Attempt any four: 20 marks
   • A. Discuss the importance of calibration of burette and pipette in titrimetry
   • B. a) Differentiate between iodometry and iodimetry
   • b) What is primary standard? Give one example
   • C. Explain the importance of drying and washing in gravimetric analysis
   • D. List various type of titration and explain neutralization titration
   • E. pH and pOH ? Prove that pH +pOH = 14
   • F. What are complexometric titration explain?
4. Q4 Attempt any four: 20 marks
   • A. Define the following terms of maximum absorption
   • B. State and derive mathematical expression for Beer's law
   • C. Draw schematic diagram of photoelectric colorimeter and discuss the instrumentation and
   • D. Molar absorptivity of a substance in a solution in a solution is 4.65 x 10 ? dm?mol a wavelength 375 nm. If the transmitters of the solution in a cell of 1 cm length length is 0.67 calculate i) the concentration of the solution ii) the concentration of the solution that wil! give the transmittance of 0.78 when placed in the cell same cell at the same wavelength
   • E. What are the deviations from Lambert’s and beer’s law
   • F. Describe photomultiplier tube with diagram
5. Q5 Attempt any four: 20 marks
   • A. Write short note on i) universe, ii) sample, iii) increment , iv) gross sample,
   • v)analysis sample
   • B. What are the various factors to be considered while choosing an analytical method?
   • C. Define the following term
   • D. What is co-precipitation and post precipitation?
   • E. State and derive mathematical expression for Lambert's ;
   • F. Explain the two different interactions possible between stimulus and analyser

Read from the scan above, so a character or two may differ. The scan is the original.