Solution:
Acid rain is caused by a chemical reaction that begins when compounds like sulphur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

Solution:
The first metal used by a man was copper.

Solution:
Many people died in London in 1952 as result of air pollution producing smog.

Solution:
Magnetite is an iron ore.

Solution:
The acidity of rainwater comes from the natural presence of three substances (CO2, NO, and SO2) found in the troposphere (the lowest layer of the atmosphere). As is seen in Table I, carbon dioxide (CO2) is present in the greatest concentration and therefore contributes the most to the natural acidity of rainwater.

Solution:
Terylene is a condensation polymer of ethylene glycol and terephthalic acid and also called polyester.

Solution:
A brown solution of raw sugar is decolourized when boiled with animal charcoal.