Environmental Chemistry

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Question 1

A water sample has ppm level concentration of following anions

F-= 10; SO42- =100; NO3-= 50

the anion/anions that make/makes the water sample unsuitable for drinking is /are:

  • only NO3-

  • both 2 SO4- and NO3-

  • only F– 

  • only SO42-

Solution

C.

only F– 

Question 2

Identify the wrong statements in the following:

  • Chlorofluorocarbons are responsible for ozone layer depletion

  • Greenhouse effect is responsible for global warming

  • Ozone layer does not permit infrared radiation from the sun to reach the earth

  • Acid rains is mostly because of oxides of nitrogen and sulphur 

Solution

C.

Ozone layer does not permit infrared radiation from the sun to reach the earth

Ozone layer does not allow ultraviolet radiation from sun to reach earth.

Question 3

The gas leaked from a storage tank of the Union Carbide plant in Bhopal tragedy was

  • Methyl isocyanate

  • Methylamine

  • Ammonia

  • Phosgene

Solution

A.

Methyl isocyanate

Methyl isocyanate CH3-N=C=O (MIC Gas) gas leaked from the storage tank of the union carbide plant in Bhopal gas tragedy.

Question 4

The smog is essentially caused by the presence of

  • O2 and O3

  • O3 and N2

  • Oxides of sulphur and nitrogen

  • O2 and N2

Solution

C.

Oxides of sulphur and nitrogen

NO, NO2, SO2 and SO3 are responsible for smog.

Question 5

The recommended concentration of fluoride ion in drinking water is up to 1 ppm as fluoride ion is required to make teeth enamel harder by converting [3Ca3 (PO4)2.Ca(OH)2] to

  • [3{Ca(OH)2}. CaF2]

  • [CaF2]

  • [3(CaF2). Ca(OH)2]

  • [3Ca3(PO4)2. CaF2]

Solution

D.

[3Ca3(PO4)2. CaF2]

3Ca3(PO4)2. Ca(OH)2] + 2F-   3Ca3(PO4)2.CaF2] Harder Teeth enamel+2OH-