Which one of the following is the main reason of acid rains ?
- A.Dissolution of sulphur and nitrogen oxides in rain
- B.Dissolution of minerals in rain
- C.Dissolution of dust particles in rain
- D.Dissolution of soil solution in rain
Correct answer
Explanation
The correct answer is A, Dissolution of sulphur and nitrogen oxides in rain. These gases react with water in the air to form sulphuric and nitric acids, which fall as acid rain.
Sulphur dioxide comes mainly from burning coal and oil in power plants and smelters, and nitrogen oxides from vehicle engines and high-temperature furnaces. In clouds they turn into H₂SO₄ and HNO₃, lowering the pH of rain below 5.6. Acid rain corrodes marble buildings such as the Taj Mahal ("stone cancer"), damages forests and makes lakes too acidic for fish.
B is wrong because minerals dissolved in rain do not make it acidic; many, like limestone, actually neutralise acids.
C is wrong because dust particles mostly make rain dirty, and alkaline dust can even raise its pH.
D is wrong because soil solution is not carried up into rain clouds and is not the source of acidity.
Exam tip: acid rain = SO₂ + NOx; normal rain has pH about 5.6, acid rain lower.
Practice Questions
View allWhich one of the following tiger reserves of India has "Bhoorsingh the Barasingha" as its official mascot ?
- A.Nameri tiger reserve
- B.Ranthambhore tiger reserve
- C.Panna tiger reserve
- D.Kanha tiger reserve
Show answer
In 2017 Kanha in Madhya Pradesh became the first tiger reserve in India to adopt an official mascot, a cartoon barasingha named Bhoorsingh.
Read the full explanation →Leakage of which one of the following gases had caused Bhopal Gas Tragedy in the year 1984 ?
- A.Methyl isocyanate
- B.Hexamethylene diisocyanate
- C.Isophorone diisocyanate
- D.Isothiocyanate
Show answer
On the night of 2-3 December 1984, methyl isocyanate (MIC) gas leaked from the Union Carbide pesticide plant in Bhopal.
Read the full explanation →Which of the following diseases are caused by the consumption of water contaminated by mercury and nitrate ?
- A.Minamata disease and Osteoporosis
- B.Osteoporosis and Blue Baby Syndrome
- C.Minamata disease and Blue Baby Syndrome
- D.Osteoporosis and Minamata disease
Show answer
Mercury in water causes Minamata disease, and excess nitrate causes blue baby syndrome.
Read the full explanation →Where is Asan Conservation Reserve located?
- A.Himachal Pradesh
- B.Uttarakhand
- C.Sikkim
- D.Arunachal Pradesh
Show answer
The Asan Conservation Reserve lies in Dehradun district of Uttarakhand. The reserve is a stretch of the Asan river near its meeting with the Yamuna, where a barrage built in 1967 created a wetland.
Read the full explanation →Excessive use of which of the following fertilizers may be responsible for the presence of a toxic substance in groundwater?
- A.Nitrogen
- B.Phosphate only
- C.Potassium only
- D.Phosphate and potassium
Show answer
Excess nitrogen fertilizer turns into nitrate, which dissolves easily, seeps down through the soil and contaminates groundwater. Urea and other nitrogen fertilizers are converted by soil bacteria into nitrate ions.
Read the full explanation →