set 3 MCQ Questions & Answers Detailed Explanation

Question : 1

Which among the following statements is false?

a) The main reason for river water pollution is industrial and domestic sewage discharge.

b) Surface water contains a lot of organic matter mineral nutrients and radioactive materials.

c) Oil slick in sea water increases D.O. value.

d) Oil spill in sea water causes heavy damage to fishery.

Question : 2

Which of the following statements about polar stratosphere clouds (PSCs) is not correct?

a) Type I clouds are formed at about –77ºC and contain solid HNO₃ . 3H₂O

b) PSCs do not react with chlorine nitrate and HCl

c) Type II clouds are formed at about –85ºC and contain some ice

d) A tight whirlpool of wind called Polar Vortex is formed which surrounds Antarctica

Question : 3

The polymeric fibre used as a substitute for wool in making synthetic blankets, sweaters, etc., is

a) orlon

b) teflon

c) nylon

d) Bakelite

Question : 4

Sewage containing organic waste should not be disposed in water bodies because it causes major water pollution. Fishes in such a polluted water die because of

a) increase in the amount of dissolved oxygen

b) decrease in the amount of dissolved oxygen in water

c) large number of mosquitoes

d) clogging of gills by mud

Question : 5

Which one of the following statements about ozone and ozone layer is true?

a) The conversion of ozone to oxygen is an endothermic reaction

b) Ozone layer is beneficial to us because ozone cuts out the ultraviolet radiation of the sun

c) Ozone has a triatomic linear molecule

d) None

Question : 6

Which one of the following is not contained in Portland cement ?

a) Ca₂SiO₄

b) Ca₃SiO₅

c) Ca₃Al₂O₆

d) Ca₃(PO₄)₂