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Pesticides are the chemical compounds used to control the damage caused by pests (insects, rodents etc.)
Example: Aldrin, Dieldrin, B.H.C etc.
Herbicides are the chemicals used to control weeds.
Example: Triazines, Sodium chlorate (NaClO₃), sodium arsenite (Na₃AsO₃).

The major sources of soil pollution are industrial wastes and agricultural pollutants like fertilizers and pesticides. Insecticides like DDT are insoluble in water and are absorbed by plant roots. Many pesticides like Aldrin and Dieldrin are toxic and non-biodegradable, which can enter the higher trophic levels through food chains, causing metabolic and physiological disorders. Industrial wastes comprise of several toxic metals such as Pb, As, Hg, Cd etc.

To control soil pollution, the addition of pollutants to the soil should be avoided. Waste materials should undergo proper treatment and recycling before dumping.

1.28 Coordination number is the number of the nearest neighbors with which a given atom is in contact. In an 
ionic crystal, the coordination number of an ion refers to the number of oppositely charged ions that 
surround that ion.
The coordination number of atoms in a
(a) Cubic close-packed structure is 12.
(b) Body-centred cubic structure is 8

Sheffield Hallam University has alumni network of more than 295,000 members worldwide. A few more notable alumni of Sheffield Hallam University are Andrew Whitfield, Mike Berners-Lee, Steven Hall, Stephanie Hill, and more. 

The amount of oxygen required by bacteria to breakdown the organic matter present in a certain volume of a sample of water is called Biochemical Oxygen Demand (BOD).

US News & World Report is known to be a globally recognised ranking body that provides education rankings of US universities for several categories, such as global, national, regional, and subject-based rankings. The US News and World Report Rankings of Stanford University are given as follows:

Yes, we observed water pollution near our area due to various human activities like toxic discharges from factories and industrial plants, runoff from agricultural fields, domestic wastes etc.

It can be controlled by preventing the toxic chemicals from entering the water bodies. Regular checks on contamination or rivers, lakes or ponds of toxic compounds need to be done. Use of chemical fertilizers should be avoided to prevent the harmful chemicals from entering the ground water.

It is a college located in Delhi which was established 1922

1.27 The different solids are classified below:
a) Ionic solids: Ammonium phosphate (NH4)3PO4), LiBr
b) Metallic solid: Brass, Rb
c) Molecular solids: Tetraphosphorous decaoxide (P4O10), Iodine (I2), P4
d) Network (covalent) solids: Graphite, SiC, Si
e) Amorphous solid: Plastics

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1.26 Quartzis crystalline solid with long range order and glass is amorphous solid (or pseudo solid or super cooled liquid) with short range order and has a tendency to flow. When quartzis heated, it can be converted into glass.

3.29.  (i) s-Block elements: ns^1-2 where n = 2-7.

(ii) p-Block elements: ns² np^1-6 where n = 2-6.

(iii) d-Block elements: (n-1)d^1-10 ns ^0-2  where n = 4-7.

(iv) f-Block elements: (n-2)f^0-14  (n-1)d^0-1 ns²where n = 6-7.

1.25 Amorphous solids have short-range order with irregular shapes of constituent particles. They have isotropic nature and melt over a range of temperatures. They do not have a definite enthalpy of fusion. Examples of amorphous solids are glass, rubber, plastic, etc.

3.28. The elements of Group I have only one electron in their respective valence shells and thus have a strong tendency to lose this electron. The tendency to lose electrons in turn, depends upon the ionization enthalpy. Since the ionization enthalpy decreases down the group therefore, the reactivity of group 1 elements increases in the order Li < Na < K < Rb < Cs. In contrast, the elements of group 17 have seven electrons in their respective valence shells and thus have strong tendency to accept one more electron to make stable configuration. So for group 17, the electron gain enthalpy and electronegativity decreases down the group and thus the reactivity also decreases.

Stanford University is known to have a good ranking for its Chemical Engineering PG, Computer Engineering PG, Global MBA, and Engineering & Technology courses.

As per the Shiksha Popularity Rankings, Stanford University has been ranked at #2 for its MS courses. Some of the other rankings of the course are given in the table below -