Test: Effects of Pollution (Old NCERT) - JEE MCQ

Ozone in the stratosphere is a product of UV radiations acting on dioxygen molecule. Ozone is a molecule that contains three oxygen atoms. At any given time, ozone molecules are constantly formed and destroyed in the stratosphere. The total amount has remained relatively stable during the decades that it has been measure

Man-made causes of depletion of ozone layer: The main cause for the depletion of ozone is determined as excessive release of chlorine and bromine from man-made compounds such as chlorofluorocarbons (CFCs).

The correct answer is Option C.

Escherichia coli ; E. coli bacteria, which causes gastrointestinal infections with symptoms including bloody diarrhea and vomiting.
 

In addition to their own resiliency, living things and the cells they are made of are protected from excessive amounts of UV radiation by a chemical called ozone. A layer of ozone in the upper atmosphere absorbs UV radiation and prevents most of it from reaching the Earth.

The amount of BOD in the water is a measure of the amount of organic material in the water, in terms of how much oxygen will be required to break it down biologically. Clean water would have BOD value of less than 5 ppm whereas highly polluted water could have a BOD value of 17 ppm or more. 

Biochemical Oxygen Demand (BOD, also called Biological Oxygen Demand) is the amount of dissolved oxygen needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.

Pesticides are poisons and, unfortunately, they can harm more than just the “pests” at which they are targeted. They are toxic, and exposure to pesticides can not only cause a number of health effects, but is linked to a range of serious illnesses and diseases in humans, from respiratory problems to cancer.

The correct answer is option A Ethanal is commercially prepared by one step oxidation of ethene in the presence of ionic catalyst in aqueous medium with a yield of 90%

Industrial wastes are classified as biodegradable and non-biodegradable wastes.
Biodegradable wastes are those types of wastes which can be recycled to new products. 
Non-biodegradable wastes are these wastes which can't be recycled and needed to dispose them properly so that  they won't create any threat to the environment.

In summer season, nitrogen dioxide and methane react with chlorine monoxide and chlorine free radicals forming chlorine sinks, preventing much ozone depletion, whereas in winters, special type of clouds, called the polar stratospheric clouds are formed over Antarctica.These polar stratospheric clouds provide surface on which chlorine nitrate gets hydrolysed to form hypochlorous acid. It also reacts with hydrogen chloride to give molecular chlorine.