In 1984, the Bhopal gas tragedy took place because methyl isocyanate

1

(a)

Reacted with ammonia

(b)

Reacted with CO₂

(c)

Reacted with water

(d)

Reacted with DDT

Common indicator organism of water pollution is

1

(a)

Eichhornia crassipes

(b)

Escherchia coli

(c)

Entamoeba histolytica

(d)

Lemna pancicostata

In a coal fired power plant electrostatic precipitators are installed to control emission of

1

(a)

NO_X

(b)

SPM

(c)

CO

(d)

SO₂

A genetically engineered microorganism used successfully in bioremediation of oil spills is a species of

1

(a)

Trichoderma

(b)

Xanthomonas

(c)

Bacillus

(d)

Pseudomonas

A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
(a) lots of urea and phosphate fertilizers were used in the crops in the vicinity
(b) the area was sprayed with DDT by an aircraft
(c) the lake water turned green and stinky
(d) phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis
Which two of the above were main reasons of fish mortality in the lake?

1

(a)

A, C

(b)

A, B

(c)

B, C

(d)

C, D

Increase in BOD in water leads to

1

(a)

increase in the disolved O₂  conc.

(b)

decrease in the dissolved O₂  conc.

(c)

maintenance of disolved O₂ conc. at the same level

(d)

no effect on dissolved O₂  conc.

Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unburnt hydrocarbons into:

1

(a)

carbon dioxide and water

(b)

carbon monoxide

(c)

methane

(d)

carbon dioxide and methene

Why is it necessary to remove sulphur from petroleum products?

1

(a)

To reduce the emission of sulphur dioxide in exhaust fumes

(b)

To increase efficiency of automobiles engines

(c)

To use sulphur removed from petroleum for commercial purposes

(d)

To increase the life span of engine silencers

Algal blooms impart a distinct colour to water due to:

1

(a)

their pigments

(b)

excretion of coloured substances 

(c)

formation of coloured chemicals in water facilitated by physiological degradation of algae. 

(d)

absorption of light by algal cell wall.

Match the items column I and column II and choose the correct option:

Column I	Column II
(a) UV	(i) Biomagnification
(b) Biodegradable Organic mater	(ii) Eutrophication
(c) DDT	(iii) Snow blindness
(d) Phosphates	(iv) BOD

1

(a)

A	B	C	D
ii	i	iv	iii

(b)

A	B	C	D
iii	ii	iv	i

(c)

A	B	C	D
iii	iv	i	ii

(d)

A	B	C	D
iii	i	iv	i