Air and Atmosphere Test - 1

During the process of respiration in plants and animals, oxygen is consumed and carbon dioxide is released. During the process of photosynthesis, green plants consume carbon dioxide and release oxygen into the atmosphere.

The level of oxygen and carbon dioxide in the atmosphere is thus maintained by plants and animals.

The oxides of sulphur and nitrogen dissolve in rain water to form sulphuric acid and nitric acid respectively and cause acid rain.

Aerosol sprays release chloroflouro carbons (CFCs) into the atmosphere rather than the ash particles. Hence, they pollute the air.

The correct order of the processes occurring in a water cycle is as follows:

Evaporation → Condensation → Precipitation → Run off

Petroleum refineries are a major source of air pollutants like sulphur dioxide and nitrogen dioxide.

When we breathe, oxygen present in the air combines with haemoglobin present in blood to form oxyhaemoglobin. This oxyhaemoglobin is then transferred to various body parts where it again dissociates to release oxygen. However, if large amount of carbon monoxide is present in inhaled air, then it combines with haemoglobin in preference to oxygen to form carboxyhaemoglobin as the affinity of carbon monoxide for haemoglobin is 325 times greater than that of oxygen. The formation of carboxyhaemoglobin cuts off oxygen supply to cells. If the condition persists for a long time, then the person can die of suffocation.

SO₂ is not a green house gas.

Oxygen is the component of air that is used in the burning of a candle. In fact, oxygen is essential for the burning of any object. Without oxygen, the process of burning cannot proceed.

Apart from the gases of nitrogen, oxygen, and carbon dioxide, particles of dust, smoke, and water vapour are also present in air. The gases of nitrogen, oxygen and carbon dioxide are not visible under sunlight. However, smoke, dust and water vapour can observed in the presence of sunlight. This is because dust, smoke, and water vapour reflect light. When a ray of sunlight enters a dark room through a tiny hole, the dust, smoke, and water vapour particles can be seen floating in air.