5
MCQ (Single Correct Answer)
Which of the following statement(s) is/are wrong?
A
Ozone is not responsible for green house effect
B
Ozone can oxidise sulphur dioxide present in the atmosphere to sulphur trioxide
C
Ozone hole is thinnig of ozone layer present in stratosphere
D
Ozone is produced in upper stratosphere by the action of $U V$ rays on oxygen
6
MCQ (Single Correct Answer)
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
large number of mosquitoes
B
increase in the amount of dissolved oxygen
C
decrease in the amount of dissolved oxygen in water
D
clogging of gills by mud
7
MCQ (Single Correct Answer)
Which of the following statements about photochemical smog is wrong?
A
It has high concentration of oxidising agents
B
It has low concentration of oxidising agent
C
It can be controlled by controlling the release of $\mathrm{NO}_2$, hydrocarbons, ozone etc
D
Plantation of some plants like pinus helps in controlling photochemical smog
8
MCQ (Single Correct Answer)
The gaseous envelope around the earth is known as atmosphere. The lowest layer of this is extended upto 10 km from sea level, this layer is
A
stratosphere
B
troposphere
C
mesosphere
D
hydrosphere
9
MCQ (Single Correct Answer)
Dinitrogen and dioxygen are main constituents of air but these do not react with each other to form oxides of nitrogen because ......... .
A
the reaction is endothermic and requires very high temperature
B
the reaction can be initiated only in presence of a catalyst
C
oxides of nitrogen are unstable
D
$\mathrm{N}_2$ and $\mathrm{O}_2$ are unreactive