CBSE Class 12 Chemistry Notes: Enviromental Chemistry – Introduction

In last 2 decades, the study of the phenomena related to the environment has gained enormous importance. Environmental pollution has becomes one of the most important issue of global concern. The branch of chemistry which deals with the study of various chemical phenomena occurring in the environment is called environmental chemistry. It is a must disciplinary science which, refer to the study of sources transport, reactions, effect & fate of certain chemical species on air, water & solid. The accessible components of environment are

(i) Atmosphere
This comprises a blanket of gaseous layer around earth.

(ii) Hydrosphere
This comprises about 96% of earths surface & includes all sources of water like oceans rivers lakes, glaciers, ground water etc.

(iii) Lithosphere
It refers to earths solid crust containing the outer mineral cover. It comprise soil, minerals, organic matter etc.

(iv) Biosphere
It refers to the domain of living organism in covalent with atmosphere hydrosphere as well as lithosphere.

Illustration 1. Name the different rexampletions of the atmosphere along with their altitudes and temperature ranges.

Solution: Troposphere (0 – 11 km, 15 to 56°C), stratosphere (11 – 50 km, – 56 to – 2°C), mesosphere (50 – 85 km, – 2 to – 92°C), thermosphere (85 – 500 km, – 92 to 1200°C)

Illustration 2. What do you mean by “Inversion temperature” in different rexampleions of the atmosphere?

Solution: When we go from one rexampleion of the atmosphere to the next adjoining rexampleion, the trend of temperature changes from increase to decrease or vice versa. This is called inversion temperature.

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