EVS/V/CC/13 Student's Copy
2 0 1 8
CBCS
5th Semester
ENVIRONMENTAL SCIENCE
SEVENTH PAPER (EVS-505)
Environmental Chemistry
Full Marks 75
Time 3 hours
PART A—OBJECTIVE
Marks 25
The figures in the margin indicate full marks for the questions
SECTION—A
Marks 10
Tick the correct answer in the brackets provided 1×10=10
1. Chemical equilibrium is the state where
both the concentrations of reactants and products are
equal
the rates of forward and backward reactions are same
no matter or energy enters into or leaves from the system
All of the above
2. Gain of oxygen, loss of electron and hydrogen is
oxidation reduction
redox reaction None of the above
/160 1 Contd.
3. The H—O—H bond angle of water molecule is
101·5° 102·5°
103·5° 104·5°
4. A radionuclide is an
atom with a suitable nucleus
atom with an unstable nucleus
atom with neither a stable nor an unstable nucleus
None of the above
5. Winkler's method is used in the determination of
DO COD
dissolved CO2 alkalinity
6. The method used for COD test is
reflux heat method reflux oxidation method
reflux digestion method reflux reduction method
7. Sodium and potassium can be analysed using
colorimeter spectrophotometer
flame photometer chromatography
8. A colorimeter functions under the principle of
spectrum-mat law stack-solubility law
Beer-Lambert law Stokes law
9. The molecules can be resolved on the basis of their distribution between a
gas and either a liquid or solid by separation method known as
gas chromatography filtration
centrifugation None of the above
10. The component in a spectrophotometer, which helps in selecting narrow
band of wavelength from the source spectrum is
phototube incandescent lamp
monochromator detector
EVS/V/CC/13/160 2 Contd.
SECTION—B
Marks 15
Write short notes on the following 3×5=15
UNIT—1
1. Characteristics of the chemical system in equilibrium
OR
2. Oxidation and reduction
UNIT—2
3. Structure of water
OR
4. Properties of water
UNIT—3
5. Colour and odour
OR
6. Difference between BOD test and COD test
UNIT—4
7. Application of colorimetry
OR
8. Components of colorimetry
UNIT—5
9. Application of gravimetric analysis
OR
10. Principles of gravimetric analysis
EVS/V/CC/13/160 3 Contd.
PART B—DESCRIPTIVE
Marks 50
The figures in the margin indicate full marks for the questions
1. What is environmental chemistry? Explain the important concept and
scope of environmental chemistry. Add a note on the need for study of
environmental chemistry.
OR
Write detailed accounts on the following 5+5=10
Conductance Sedimentation
2. Define surfactants. Discuss the types and effects of surfactants. 2+8=10
OR
Write short notes on the following 5+5=10
Organic and inorganic compounds
Saturated and unsaturated hydrocarbons
3. What is dissolved oxygen? Describe the principle, procedure and
environmental significance for estimation of dissolved oxygen in water. 2+8=10
OR
Give detailed accounts on the following 5+5=10
Nitrogen analysis Phosphorous analysis
4. What do you mean by titration? Discuss the procedure and different types
of titration. 2+8=10
OR
What is flame photometer? Explain the working principle and application of
a flame photometer. 2+8=10
5. What do you understand by chromatography? Describe, in detail, the
working principle and application of chromatography in environmental
analysis. 2+8=10
OR
What is spectrophotometry? Write, in detail, the working principle,
components and application of spectrophotometry. 2+8=10