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
10
MCQ (Single Correct Answer)
The pollutants which come directly in the air from sources are called primary pollutants. Primary pollutants are sometimes converted into secondary pollutants. Which of the following belongs to secondary air pollutants?
A
CO
B
Hydrocarbon
C
Peroxyacetyl nitrate
D
NO
11
MCQ (Single Correct Answer)
Which of the following statements is correct?
A
Ozone hole is a hole formed in stratosphere from which ozone oozes out
B
Ozone hole is a hole formed in troposphere from which ozone oozes out
C
Ozone hole is thinning of ozone layer of stratosphere at some places
D
Ozone hole means vanishing of ozone layer around the earth completely
12
MCQ (Single Correct Answer)
Which of the following practices will not come under green chemistry?
A
If possible, making use of soap made of vegetable oils instead of using synthetic detergents
B
Using $\mathrm{H}_2 \mathrm{O}_2$ for bleaching purpose instead of using chlorine based bleaching agents
C
Using bicycle for travelling small distances instead of using petrol/ diesel based vehicles
D
Using plastic cans for neatly storing substances