IGNOU MSCANCHEM MCH 23 Environmental Chemistry Solved Assignment ENGLISH

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MCH 023 (July 2026) - ENGLISH

Tutor Marked Assignment
MCH-023: ENVIRONMENTAL CHEMISTRY
Course Code: MCH-023
Assignment Code: MCH-023/TMA/2026
Maximum Marks: 100
Note: Answer all the questions given below.
1. a) Explain the following in brief. (5)
 i) Soil profile
 ii) Topography
 iii) Parent material
 iv) Metamorphic rocks
 v) Granular disintegration
 b) How is the soil texture analysis done? Describe in brief. (5)
2. a) Describe the reasons of soil alkalinity and the consequences of the same. (5)
 b) How is nitrogen important to the plants? Write the sources of this macronutrient
to plants. (5)
3. a) What is meant by the cation exchange capacity (CEC) of soils? What is the property
of soil that determines the CEC of soils? How does CEC vary with pH? (5)
 b) Describe the distribution of the world’s water resources among oceans, icecaps/
glaciers, groundwater, and surface water, providing approximate percentages. (5)
4. a) Explain the importance of groundwater as a water resource in India. What are the
problems in overusing ground water? (5)
 b) Define turbidity in water and explain its causes, measurement, and significance for
water quality. (5)
5. a) Briefly explain the factors affecting water quality. (5)
 b) State the five “designated best uses” of water as per the Central Pollution Control
Board (CPCB) classification and give one corresponding primary water quality
criterion for each. (5)
6. a) What is meant by the atmospheric effect and the greenhouse effect? (5)
 b) Explain how ozone layer depletion is related to global warming. (5)
7 a) How do the following factors affect the discharge of pollutants in the atmosphere? (5)
i) Atmospheric stability ii) Temperature iii) Precipitation
 iv) Turbulence v) Solar radiation
 b) Distinguish between the following pairs giving examples: (5)
 i) Stationary and Mobile sources of pollutants
 ii) Indoor and Ambient air poll

MCH 023 (July 2025 - January 2026) - ENGLISH

Tutor Marked Assignment
ENVIONMENTAL CHEMISTRY
Course Code: MCH-023
Assignment Code: MCH-023/TMA/2026
Maximum Marks: 100
Note: Answer all the questions given below:
1. (a) i) Soil Profile: Section of soil showing characteristic horizons (1)
ii) Topography: A passive factor of soil formation indicating the location of a soil on a
landscape (1)
iii) Parent material: A passive soil former referring to the primary material from which
soil is formed. (1)
iv) Metamophic rocks: Igneous and sedimentary rocks that have been altered from their
previous condition by combined action of heat and pressure below Earth’s surface. (1)
v) Granular disintegration: Breaking up of the igneous rock into separate grains by
action of ice, water and wind. (1)
(b) Soil texture analysis is done on the basis of relative proportions of sand, silt and clay. (1)
Any two methods as per page 30, Block-1, along with explanation. (2 + 2)
2. (a) Soil alkalinity is due to high base saturation particularly with sodium and presence of free
carbonates of Ca and Na. (1)
Disadvantages:
i) Non availability of N, P (1)
ii) Non availability of metal ions and growth retardation (1)
(b) Any two benefits of N: carbohydrate utilization Plant growth, Part of number of
biomolecules (1 + 1)
3. (c) i) High melting point of water (1)
ii) Lower density of ice (1)
iii) High surface tension helps in movement of water (1)
(d) i) Accumulation of water around the roots of plants.
ii) underground water may rize.
iii) Air flow to roots may be affected etc.(any 2-3 points from Pg. 18, Block 2) (2)
3. (a) Reverse osmosis (Pg.25, Block 2)- water moves through semipermeable membrane
leaving the dissolved ions behind ……………(Margin remark)
(b) JTU- Jackson turbidity unit
NTU-Nephelometric turbidity unit (2)
(c) 1pmm=1 milligram ∕ kilogram
= 10-3
g ∕ line (1)
(d) Sulphates in water systems originate from the oxidation of sulphide ores and their
dissolution.
2Fe S2+H2O+15 [0] → Fe2(SO4)3+H2SO4
FeS2+7[0]+H2O→ FeSO4+H2SO4
2FeSO4+H2SO4+[0]→ Fe (SO4)3+H2O (3)
(3) The portion of hardness that disappears after prolonged boiling is called temporary hardness
and is mainly due to bicarbonates. O2 boiling CaCO3 or Mg CO3 is obtained as a
precipitate along with the evolution of CO2
(2)
4. a) Atmospheric effect: the effect caused by the atmosphere of earth on the temperature which
would have been much lower in the absence of atmosphere. (1)
Greenhouse effect: Absorption of earth’s radiation by atmosphere due to the presence of
greenhouse gases (1)
b) By reducing the effectiveness of CO2 sink in ocean which is due to the presence of
phytoplanktons in the ocean. Due to ozone layer depletion the high energy radiations reach
the oceans killing the planktons p-25 (Block 3) (3)
c) Explanation as per pages 30-38 (Block 3)
i) p-34 ii) p-33 iii) p-36 iv) p-31 v) p-38 (1

5)
5. a) i) Stationary sources of pollutants: due to emissions of the structures that are
 fixed at one place e/q/ industrial, residential, power plants, solid waste
burning
½ +½
Mobile sources: emissions of moving structures e.q. motor vehicles, highway ½
vehicles, trains

ii) Indoor air Pollution: Present within building Premises e.q. tobacco smoke, CO, NOx
, lead, Rn
etc
e.q. SOx, organic compounds, CO,, NOx etc. ½
b) Cu & Ag tarnish rapidly in presence of H2S. the sulphide wating formed on
the electrical contacts can increase resistance across contacts. (2)
p-66 (Block 3)
c) Sample size, rate of sampling Sampling duration, storage and handling Explanation (2)
(p- 81,82, Block)
6. (a) i) Constituents in a dairy waste are mainly organic matter and have high (½)
oxygen demand. (½)
They also contain nitrogen and phosphorus
Treatment Systems: Aeration or modified activated sludge, Trickling filters, Irrigation
and Lagooning (½4)
Important features of any one of the methods given
(Ref. p. 17-18, Block 4) (2)
(b) Pesticides can enter water in following ways:
i) Intentional application for pest control: examples or subpoints given (1½)
ii) Unintentional spread during pest control-further examples of this given (1½)
iii) Discharge of pesticide wastes while manufacturing/or during formulation stages (1)
iv) Incorporation of treated foliage into water. (1)
7. (a) Chemical characteristics of sewage
i) Inorganic: Presence of sand and dissolved mineral matter consisting of sulphates,
carbonates and chlorides of calcium, magnesium, sodium, potassium and iron. (1)
Effect on treatment systems: Iron salts precipitate out in aeration tanks of activated
sludge plants and trickling filters and cause clogging. (1)
ii) Organic: Contain proteins, carbohydrates and fats (1)
Effects
Proteins lead to nitrogen waste and decompose to CO2 and NH3.
(½)
Carbohydrates produce organic acids which lower the pH. (½)
Fats Make the sewage treatment difficult by making coating on walls of tanks and
channels, organic particles and also form scum. (1)
(b) Organochlorine compounds causing water pollution are
DDT, aldrin, endosulfan, 2, 4, 5-T, hexachlorobenzene, pentachlorophenol etc. (2)
Sources
• agricultural run-off and (½)
• discharge of industrial wastes
(½)
Presence in traces is in due to
• their low solubility in water and (½)
• tendency to be absorbed on solid surfaces. (½)
Their toxicity affects liver, central nervous system and heart. (1)
8. a) i) Organic ii) 40C iii) physical iv) dark and at low temperature (1x 4)

b) i) Solute should have high solubility in it
ii) should not be expensive any
iii) low boiling point four (½ x 4)
iv) non reactive with solute
v) immiscible with other solvent
c) Comparing the Rf value with pure compound
Explanation p-47 (Block 5 (2)
d) Based on distribution ratios between the water saturated cellulose
(stationary phase)4 the developing liquid (Mobile phase) (p-50, Block 5) (2)

9. a) i) Mole: Signifies 6.023 X 1023 molecules (in no.) In a compound and the gram molecular
weight in amount (1)
 n = w / gmw
ii) Mole fraction: Ratis of No. of moles of the component to the total no. of moles of all the
 component in a solution (1)
 iii) Redox titration: in which an oxidation and reduction process take place during the titration
 (1)
 iv) Complexometric titration: Titration involves a process of cmplexation (1)
 b) Gravimetric Analysis: it is fending the amount of a given component from the result of
weighing. Volumetric analysis: The mass is calculated by knowing the volume of Reagent of
known concentration during titration
½
c) SHE- reference electrode contracted from Pt foil plate coated with Pt bl (p012-13 Block 6 )
can be used for entire pH range, high accuracy reagent purification, not -affected
by mechanical stress (2)
Limitations : Not with oxidesing reducing agents / transfer from one place to other not easy,
Pt surface poisoned by H2 S, CN—& Hg. (2)

10 (a) Discussion n the advantages of atomic absorption spectrophotometer method over flame
emission method (3)
Drawing a schematic diagram of are atomic absorption spectrophotometer (2)
(b) Indicator microorganisms: They serve as an ‘alarm’ system. Their presence in water system is
indicator of water pollution due to pathogenic microorganism. e.g. Enchiridia coli,
Enterobacter (2)

Important characteristic of an indictor microorganism (Pl Block 6 pp 75) 

MCH 023 (January 2026 - July 2026) - ENGLISH

Tutor Marked Assignment

MCH-023: ENVIRONMENTAL CHEMISTRY

Course Code: MCH-023

Assignment Code: MCH-023/ΓΜΑ/2025-26

Maximum Marks: 100

Note: Answer all the questions given below.

1. a) Explain the following in brief.

i) Soil profile

ii) Topography

iii) Parent material

iv) Metamorphic rocks

v) Granular disintegration

How is the soil texture analysis done? Describe in brief. b)

2. a) Describe the reasons of soil alkalinity and the consequences of the same.

b) How is nitrogen important to the plants? Write the sources of this macronutrient to plants.

3. a) What is meant by the cation exchange capacity (CEC) of soils? What is the property of soil that determines the CEC of soils? How does CEC vary with pH?

b) Describe the distribution of the world's water resources among oceans, icecaps/glaciers, groundwater, and surface water, providing approximate percentages.

4. a) Explain the importance of groundwater as a water resource in India. What are the problems in overusing ground water?

b) Define turbidity in water and explain its causes, measurement, and significance for water quality.

5. a) Briefly explain the factors affecting water quality.

b) State the five "designated best uses" of water as per the Central Pollution Control Board (CPCB) classification and give one corresponding primary water quality criterion for each.

6. a) What is meant by the atmospheric effect and the greenhouse effect?

b) Explain how ozone layer depletion is related to global warming.

7 a) How do the following factors affect the discharge of pollutants in the atmosphere?

i) Atmospheric stability

ii) Temperature

iii) Precipitation

iv) Turbulence

v) Solar radiation

b) Distinguish between the following pairs giving examples:

i) Stationary and Mobile sources of pollutants

ii) Indoor and Ambient air pollution

8. a) Name any two methods that are used for collecting gaseous samples and explain any one of these.

b) Briefly explain the following terms:

i) Dissolved Oxygen (DO)

ii) Biochemical Oxygen Demand (BOD)

9. a) Discuss the method of aeration in the treatment of daily wastes. Also give the problems associated with it.

b) Give the characteristics of an ideal pesticide.

10. a) In which form the phosphorous occurs in sewage? Also, briefly explain the methods of removing it.

b) How are Pathogenic bacteria transmitted in water? List any five diseases transmitted by them.

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