BSc Chemistry SEM V 2018 19 2018-19 Chemistry IV Analytical Chemistry 19 Old Question Paper - Mumbai University | munotes

Questions asked in this paper

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1. Q3 Use of logtables/non-programmable calculator is allowed Answer any three of the following
   • A. Name three types of systematic errors. Explain the terms constant errors and proportionate errors, 5 with suitable examples
   • B. In acertain electrochemical process, the quantity of electricity consumed in coulombs were as 5
   • C. of portland cement containing 50% CaO by weight on anaylsis, yielded the following 5 Weight of Ca0 Calculate: 1) absolute error, and 1i) relative error in parts per thousand
   • D. Describe the technique of sampling of immiscible and homogeneous stationary liquid. 5
   • E. Discuss the importance of particle size and sample size with respect to sampling of solids. 5
   • F. Explain the use of various reagents and fluxes in the dissolution of sample. Name any twocommon 5
2. Q2 Answer any three of the following
   • A. Discuss the nature of titration curve for the titration of strong acid against strong base, justifying 5 the choice of suitable indicators
   • B. Discuss the choice of indicators in the titration of 10.0 of 0.1M acetic acid (Ka=1.8x10> ) 5 against 0.1M NaOH, with the help of pH calculations as under:
3. Q1 at half the equivalence point
   • ii) at the equivalence point
   • iii) on addition of 10.1 em? of titrant
   • C. Discuss Volhard’s method for the estimation of chloride ions by back titration, explaining the 5 techniques to minimize errors
   • D. Describe the determination of end point by Fajan’s method in precipition titration. 5
   • E. Name the different light dispersing devices used in UV-Visible spectrophotometer and describe 5 any one in detail
   • F. With help of neat labelled diagram, explain the function of components in a single beam 5
   • Q.P. Code : 40603
4. Q3 Answer any three of the following
   • A. Explain the term chromatography. Discuss the classification of chromatographic technique based 5 on the nature of phases involved, giving suitable examples
   • B. 0.1 dm? of 1M aqueous phase of Fe** is to be extracted with portions of ether. Calculate how 5 many extractions are necessary so as to bring the concentration of Fe** in the aqueous solution to
   • C. Ninety percent of metal chelate is extracted, when equal volumes of aqueous and organic phases 5 were used. What will be the percentage extraction, if the volume of organic phase in tripled?
   • D. State Nernst distribution law. Explain the following with respect to solvent extraction. 5
5. Q1 Role of complexing agent, and
   • E. Discuss the principle and any two applications of paper chromatography. 5
   • F. Explain the following with respect to TLC. 5
6. Q1 Preparation of chromatoplate
   • ii) Any two advantages over paper chormatography
7. Q4 Attempt any three of the following
   • A. With the help of a schematic diagram, discuss the construction and working of electrothermal 5 atomizer in AAS
   • B. Draw a neat labelled diagram of a flame photometer and explain the function of each components. 5
   • C. Discuss the following with respect to AAS, 5
   • i) Radiation source, and
   • ii) Role of chopper
   • D. Discuss the effect of concentration of solution and particle size on scattering of light by solid 5
   • E. Discuss the following with respect to tubidimetry. 5
8. Q1 Determination of molecular weight of macromolecules, and
   • F. Describe the basic principle of fluorimetry. 5 Fillin the blanks. 4
   • a) Median of the set of observations 19.8,19.1 =
   • b) The agreement among the numerical values of the replicate set recorded in an identical fashion is
   • c) Anaccurately weighed amount of taken for analysis is called the analysis sample
   • d) Displacement method is one of the methods used for sampling of
   • A. State true or false. 4
   • p) The true value of a measurement is never known exactly
   • Q.P. Code : 40603
   • q) Systematic errors affect the accuracy of the results
   • r) Coning and quartering is used for reducing the particle size
   • s) Random sampling is the selection of sample with bias
9. Q5 B. the blanks. 4 marks
   • a) Fora titration of weak acid again weak base, pH changes are near the
   • b) In Mohr’s method, used as an indicator
   • c) Absorbance determination are always carried out at wavelength of absorption
   • d) In the titration of 0.1M acetic acid versus 0.1M ammonium hydroxide, pH at the equivalence point
   • B. State true or false. 4
   • p) Mixed indicators are generally used for the titration of weak acid of weak base
   • q) In Mohr’s method, pH of the solution to be titrated should be preferably between 4.6 to 6.9
   • r) Absorption curve in spectrophotometer is a plot of absorbance versus concentration of the solution
   • s) Mohr’s method can be used for titration of iodide and thiocyanate
10. Q5 C. the blanks. 4 marks
    • a) According to Bush-Densen equation, for given Da and Dg values, =
    • b) InTLC, value is used for qualitative analysis
    • c) Insolvent extraction, for a given aystem, [Cw]= 2x107M, [Co]= then Dow=
    • d) The choice of best possible developing solvent in paper chromatography depends on single facts that retardation factor should be for different components in the given mixture
    • C. State true or false. 4
    • p) The process of locating analyte on a thin layer plate is often termed as visualization
    • q) is constant for a given system even under varying experimental conditions
    • r) TLC has become workhorse of drug industry for determination of product purity
    • s) In solvent extraction, singled step extraction using large volumes of extractant is more efficient than multistep extraction using small volumes Q:5 D. Fillin the blanks. 3
    • a) Liquid is used to cool the sample to enhance the phenomenon of phosphorescence
    • b) Phosphoroscope is a device that helps to measure in presence of fluorescence
    • c) The instrument used to measure turbidance is known as
    • D. State true or false. 3
    • p) Flame serves as a radiation source for different elements in AAS
    • q) The life time of phosphorescence is much larger than fluorescence
    • r) AAS is independent of flame temperature

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