Practice MCQ Questions and answers on Chemistry-GK

21

The water pollution in river is measured by the dissolved amount of

A) Chlorine B) Ozone C) Nitrogen D) Oxygen

Discuss

Answer & Solution

Answer: Option D

Solution:

Water pollution in river or any other water body is measured by amount of dissolved oxygen.

22

Ultraviolet rays can be used in water treatment as

A) Flocculator B) Precipitator C) Hydrolyser D) Disinfectant

Discuss

Answer & Solution

Answer: Option D

Solution:

UV radiation can be an effective viricide and bactericide. Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in drinking water treatment.

23

Tar roads get damaged if there is

A) Stagnation of water on road B) Heavy traffic C) No maintenance D) No sloping

Discuss

Answer & Solution

Answer: Option A

Solution:

Tar roads gets damaged easily during rainy season. This is because tar roads are prone to water damage very quickly. In the tar road, bitumen plays an important road to create a bond between the aggregate. But, tar road does not give more strength than concrete road, because bitumen respond to heat and water.

24

Aerated water contains

A) SO₂ B) NO₂ C) H₂
D) CO₂

Discuss

Answer & Solution

Answer: Option D

Solution:

Aerated water is, correctly speaking, water to which air is added. So aerated water is any water artificially impregnated with a large amount of gas (as carbon dioxide). The term is, however, frequently applied to carbonated water.

25

The BOD values of water indicate the

A) Amount of organic debris B) Amount of oxygen used for biochemical oxidation C) Amount of oxygen used for biochemical reduction D) Amount of ozone used for biochemical oxidation

Discuss

Answer & Solution

Answer: Option B

Solution:

Clean water has BOD which is less than 5 ppm. If it is equal to or more than 12 ppm, then the water is considered as polluted. So this indicates water be rich in dissolved oxygen, that helps the microorganisms to oxidize inorganic and organic materials.

26

Iron and manganese present as pollutants in water cannot be removed by________

A) Oxidation followed by settling and filtration B) Chlorination C) Ion exchange process D) Lime soda process or manganese zeolite process

Discuss

Answer & Solution

Answer: Option B

Solution:

Water chlorination is the process of adding chlorine or hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is highly toxic. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, typhoid etc.

27

Table salt gets moist during rainy season because

A) Sodium chloride is hygroscopic
B) Sodium chloride is deliquescent C) Sodium chloride contains some quantity of sodium iodide D) Sodium chloride contains hygroscopic impurities like magnesium chloride

Discuss

Answer & Solution

Answer: Option D

Solution:

Table salt is refined salt, which contains about 97 to 99 percent sodium chloride. It usually contains substances that make it free-flowing (anticaking agents) such as sodium aluminosilicate or magnesium carbonate. Because of Hygroscopic nature of salt it become wet in rainy season as the salt absorbs moisture from environment.

28

The unit to measure the flow of water is

A) Micro Mho B) Ohm meter C) Milli curie D) Cusecs

Discuss

Answer & Solution

Answer: Option D

Solution:

The unit to measure the flow of water is cusecs. Cusecs is short form of Cubic feet per second.

29

When water itself combines chemically with some element or mineral it is called

A) Carbonation B) Desilication
C) Hydration D) Oxidation

Discuss

Answer & Solution

Answer: Option C

Solution:

When water itself combines chemically with some element or mineral it is called hydration.

30

Sea water is saltier than rain water because

A) Sea animals are salt producing B) The air around the sea is saltish
C) Rivers wash away salts from earth and pour them into the sea D) Sea beds have salt producing mines

Discuss

Answer & Solution

Answer: Option C

Solution:

Sea water is saltier than rain water because river wash away salts from earth and pour them into the sea. Rain water is mostly pure water. Sea water has salt (and other minerals) dissolved in it. Water evaporates from the sea to form clouds (which eventually cause rain) - but the salt is left behind in the ocean. Thus, you can't have salt-water rain.