Question

Ozone layer is present in the:
A. Troposphere
B. Stratosphere
C. Ionosphere
D. Ozonosphere

Answer 1

Hint: The Earth is surrounded by a blanket of gases, which is held near the surface of the Earth with the help of gravitational force. These layers of gases collectively form our atmosphere. There are several layers known by different names. In one such layer, we have an ozone layer which protects the earth from harmful $UV$ rays.

Complete step by step answer:
 The ozone layer is a gaseous layer situated in the atmosphere, it consists of ozone gas which is three molecules of oxygen combined. It helps to trap harmful $UV$ rays so that it cannot affect the lives on the Earth.
Ozone acts as a protective layer which absorbs all the harmful ultraviolet rays, which directly comes from the sun. The ultraviolet rays, if allowed to enter the Earth atmosphere, can lead to serious damages of lives. The formation of ozone happens when ${O_2}$ molecule reacts with $UV$ rays resulting in two $O$ atoms, this $O$ atoms, in turn, reacts with ${O_2}$ molecules to form two molecules of ${O_3}$.
Now, the atmosphere consists of different layers, that is exosphere, thermosphere, mesosphere, stratosphere, troposphere. And the stratosphere is the second most layer from the surface of the earth where the ozone layer is present.

Hence, option B is correct.

Additional information:
Ozone acts as a strong oxidising agent, as ${O_3}$ molecule decomposes it provides a nascent oxygen molecule which is a strong oxidising agent as compared to oxygen itself. It oxidizes the other substance by reducing its electrons.

Note:
Oxidation- when an electronegative atom such as oxygen, halogens, is added to an atom/molecule then the atom/molecule is said to undergo oxidation.
“Oxidation: loss of an electron.”
Reduction- when any electropositive atom such as hydrogen, is added to an atom/molecule then the atom/molecule is said to undergo reduction.
“Reduction: addition of an electron.”