Class 11 Chemistry - Chapter Environmental Chemistry NCERT Solutions | What are the major causes of water pollu
What are the major causes of water pollution? Explain.
Water pollution arises as a result of several human activities, which leads to the presence of several undesirable substances in water. Major water pollutants with their sources have been tabulated as follows:
| Pollutant | Source |
| Radioactive substances | Mining of uranium-containing minerals |
| Heat | Water used for cooling in industries |
|
Plant nutrients
|
Chemical fertilizers |
| Toxic heavy metals | Chemical factories and industries |
| Sediments | Strip mining and soil erosion |
| Pesticides | Chemicals used for killing fungi, weed, insects |
|
Micro-organisms |
Domestic sewage |
| Organic wastes | Domestic sewage, decaying animals and plants, animal excreta and waste, discharge from food processing industries |
Roles played by major pollutants are:
1. Pathogens: These water pollutants include bacteria and other organisms. They enter water from animal excreta and domestic sewage. Bacteria present in human excreta (for example, Escherichia coli and Streptococcus faecalis) cause gastrointestinal diseases.
2. Organic wastes: These are biodegradable wastes that pollute water as a result of run off. The presence of excess organic wastes in water decreases the amount of oxygen held by water. This decrease in the amount of dissolved oxygen inhibits aquatic life.
3. Chemical pollutants: These are water soluble chemicals like heavy metals such as cadmium, mercury, nickel, etc. The presence of these chemicals (above the tolerance limit) can damage the kidneys, central nervous system, and liver.
More Questions From Class 11 Chemistry - Chapter Environmental Chemistry
- Q:-
Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?
- Q:-
What are the harmful effects of photochemical smog and how can they be controlled?
- Q:-
Write down the reactions involved during the formation of photochemical smog.
- Q:-
Explain tropospheric pollution in 100 words.
- Q:-
What are the reactions involved for ozone layer depletion in the stratosphere?
- Q:-
What would have happened if the greenhouse gases were totally missing in the earth's atmosphere? Discuss.
- Q:-
Statues and monuments in India are affected by acid rain. How?
- Q:-
What do you mean by green chemistry? How will it help decrease environmental pollution?
- Q:-
What is smog? How is classical smog different from photochemical smog?
- Q:-
What do you mean by ozone hole? What are its consequences?
Popular Questions of Class 11 Chemistry
- Q:-
How do you account for the formation of ethane during chlorination of methane?
- Q:-
What are hybridisation states of each carbon atom in the following compounds ?
(i) CH2=C=O,
(ii) CH3CH=CH2,
(iii) (CH3)2CO,
(iv) CH2=CHCN,
(v) C6H6
- Q:-
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
- Q:-
What are the common physical and chemical features of alkali metals?
- Q:-
Calculate the molecular mass of the following:
(i) H2O
(ii) CO2
(iii) CH4 - Q:-
Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O
- Q:-
What is the basic theme of organisation in the periodic table?
- Q:-
Explain the formation of a chemical bond.
- Q:-
Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only. - Q:-
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?
Recently Viewed Questions of Class 11 Chemistry
- Q:-
What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.
(i) F–
(ii) Ar
(iii) Mg2+
(iv) Rb+
- Q:-
Addition of HBr to propene yields 2-bromopropane, while in the presence of benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give mechanism.
- Q:-
Complete the following chemical reactions.
(i) PbS(s) + H2O2(aq) →
(ii) MnO-4(aq) + H2O2(aq) →
(iii) CaO(s) + H2O(g) →
(iv) AlCl3(g) + H2O(I) →
(v) Ca3N2(s) + H2O(I) →
Classify the above into (a) hydrolysis, (b) redox and (c) hydration reactions.
- Q:-
Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process?
- Q:-
Among the following pairs of orbitals which orbital will experience the larger effective nuclear charge?
(i) 2s and 3s,
(ii) 4d and 4f,
(iii) 3d and 3p
- Q:-
H3PO3 can be represented by structures 1 and 2 shown below. Can these two structures be taken as the canonical forms of the resonance hybrid representing H3PO3? If not, give reasons for the same.
- Q:-
Find out the value of Kc for each of the following equilibria from the value of Kp:
(i) 2NOCl (g) ↔ 2NO (g) + Cl2 (g); Kp = 1.8 × 10–2 at 500 K
(ii) CaCO3 (s) ↔ CaO(s) + CO2(g); Kp = 167 at 1073 K
- Q:-
The enthalpies of all elements in their standard states are:
(i) unity
(ii) zero
(iii) < 0
(iv) different for each element
- Q:-
Indicate the σ and π bonds in the following molecules :
(i) C6H6,
(ii) C6H12,
(iii) CH2Cl2,
(iv) CH2=C=CH2,
(v) CH3NO2,
(vi) HCONHCH3
- Q:-
Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, E+
(a) Chlorobenzene, 2,4-dinitrochlorobenzene, p-nitrochlorobenzene
(b) Toluene, p-H3C-C6H4-NO2, p-O2N-C6H4-NO2.
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