Chemistry (Part-XVI)

Total Questions: 50

21. Which of the following is a greenhouse gas or a gas which can deplete the ozone layer? [S.S.C. Online CHSL (T-I) 31.01.2017 (Shift-I) ]

(a) BCI₃
(b) Ni(CO)₄
(c) CH₃OH
(d) CCIF₃

Correct Answer: (d) CCIF₃

Solution:CCIF₃ (Chlorotrifluoromethane or CFC-13): This is a Chlorofluorocarbon (CFC). CFCs are well-known to be both powerful greenhouse gases (they have very high Global Warming Potentials, e.g., CFC-13 has a GWP of 14,000) and major ozone-depleting substances.

22. Which of the following is a greenhouse gas or a gas which can deplete the ozone layer? [S.S.C. Online CHSL (T-I) 3.02.2017 (Shift-II) ]

(a) BF₃
(b) O₂
(c) CHCIF₂
(d) Cl₂

Correct Answer: (c) CHCIF₂

Solution:CHCIF₂ (Chlorodifluoromethane or HCFC-22): This is a Hydrochlorofluorocarbon (HCFC). HCFCs were introduced as transitional alternatives to CFCs because they have a lower, but still significant, ozone-depleting potential (ODP = 0.055) and are also potent greenhouse gases (GWP = 1,760).

23. Which of the following is a greenhouse gas or a gas, which can deplete the ozone layer? [S.S.C. Online CHSL (T-I) 30.01.2017 (Shift-II) ]

(a) As
(b) Kr
(c) C₄H₈
(d) CH₄

Correct Answer: (d) CH₄

Solution: $C H₄$ (Methane): Methane is a potent greenhouse gas, second only to carbon dioxide in its contribution to human-induced global warming. While it doesn't directly deplete the ozone layer in the same way as CFCs, it does influence stratospheric chemistry and can indirectly affect ozone.

24. How many oxygen atoms are there in a molecule of Ozone? [S.S.C. Online MTS (T-I) 12.10.2021 (Shift-III) ]

(a) Three
(b) Two
(c) Four
(d) One

Correct Answer: (a) Three

Solution:

The chemical formula for ozone is $O₃$ . This means that one molecule of ozone is composed of three oxygen atoms. This distinguishes it from diatomic oxygen ( $O ₂$ ), which is the form of oxygen we breathe and consists of two oxygen atoms.

25. Which of the following is NOT a greenhouse gas? [S.S.C. Online CGL (T-I) 17.08.2021 (Shift-I) ]

(a) Helium
(b) Nitrous oxide
(c) Water vapour
(d) Surface level ozone

Correct Answer: (a) Helium

Solution:Helium is not a greenhouse gas. Greenhouse gases include carbon dioxide, methane, water vapor, nitrous oxide, and fluorinated gases. These gases are found naturally in the atmosphere.

26. What is the Green House Effect? [S.S.C. Online MTS (T-I) 17.09.2017 (Shift-III) ]

(a) turning green in the house due to being covered with algae.
(b) turning green in the house due to the green component of white light.
(c) heating of the earth by the radiation intercepted by the earth's atmosphere.
(d) none of these

Correct Answer: (c) heating of the earth by the radiation intercepted by the earth's atmosphere.

Solution:The greenhouse effect or greenhouse effect is the increase in the temperature of the earth and its surrounding atmosphere. This effect is caused by an increase in the number of certain gases in the atmosphere, which absorbs thermal radiation. For example, CO₂ water vapor, N₂O, methane, etc.

27. _____ gases trap heat in the atmosphere which makes the Earth warmer, causing global warming. [S.S.C. Online Graduate Level (T-I) 12.06.2019 (Shift-III) ]

(a) Elemental
(b) Compound
(c) Nobel
(d) Greenhouse

Correct Answer: (d) Greenhouse

Solution:Greenhouse gases (such as CO₂, water vapor, nitrous oxide, and chlorofluorocarbons) trap heat in the atmosphere, increasing the temperature of the Earth. This process is called global warming.

28. Which of the following destroys the ozone layer? [S.S.C. Online Graduate Level (T-I) 6.06.2019 (Shift-I) ]

(a) Silicon
(b) Sulphur
(c) Carbon
(d) Chlorine

Correct Answer: (d) Chlorine

Solution:The chlorine present in chlorofluorocarbons or freon damages or destroys the ozone layer. Freon is a volatile gas used in industrial refrigerants and air conditioners that, upon reaching the atmosphere, releases chlorine from the effects of ultraviolet rays, which cause ozone depletion.

29. Which of the following pollutants is a secondary pollutant? [S.S.C. Online MTS (T-I) 21.08.2019 (Shift-I) ]

(a) Ozone
(b) Nitrogen oxide
(c) Carbon monoxide
(d) Sulfur dioxide

Correct Answer: (a) Ozone

Solution:Secondary pollutants are not emitted directly from a source, as ozone (O₃) gas is a secondary pollutant. The gases that are produced directly from a source and enter the atmosphere as pollutants are primary pollutants. Gases such as nitrogen oxide (NO₂), carbon monoxide (CO), and sulfur dioxide are the primary pollutants.

30. Name the International treaty designed to protect the ozone layer from CFCs. [S.S.C. Online CHSL (T-I) 24.01.2017 (Shift-II) ]

(a) Sigma Protocol
(b) Montreal Protocol
(c) Ozone Protocol
(d) Green Protocol

Correct Answer: (b) Montreal Protocol

Solution:Montreal Protocol: The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances responsible for ozone depletion. It was signed in 1987 and is widely considered one of the most successful international environmental agreements. It specifically targeted CFCs, halons, and other ozone-depleting substances.

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