Chemistry (Part-XVI)

Total Questions: 50

31. There is a protocol signed to reduce production of CFC, known as _____ . [S.S.C. Online CHSL (T-I) 11.01.2017 (Shift-III) ]

(a) CFC Protocol
(b) IR Protocol
(c) Montreal Protocol
(d) UV Protocol

Correct Answer: (c) 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.

32. What is the effect of greenhouse gases on the average temperature of the Earth's atmosphere? [S.S.C. Online MTS (T-I) 16.09.2017 (Shift-I)]

(a) increases
(b) decreases
(c) remains same
(d) first increases and then decreases.

Correct Answer: (a) increases

Solution:Greenhouse gases are responsible for the planet's atmosphere or climate change and ultimately global warming. Most of these gases are carbon dioxide, nitrous oxide, methane, chlorofluorocarbons, vapor, ozone, etc.

33. Which of the following countries is the largest per capita emitter of carbon dioxide in the world? [C.P.O. S.I. 11.06.2016 (Shift-I) ]

(a) Saudi Arabia
(b) Qatar
(c) the United States
(d) India

Correct Answer: (b) Qatar

Solution:According to World Bank data, Qatar is the world's highest per capita emitter of carbon dioxide. Qatar's per capita carbon dioxide emissions in 2013 were 40.5 metric tons, while Saudi Arabia's was 17.9 and India's 1.6 metric tons. According to 2014 World Bank data, Qatar's per capita carbon dioxide emissions were 45.4 metric tons, while Saudi Arabia's was 19.5 metric tons, the United States 16.5 metric tons and India's was 1.7 metric tons.

34. The substances which contaminate the air are called- [S.S.C. Online MTS (T-I) 30.10.2017 (Shift-I) ]

(a) Smoke
(b) Air pollutant
(c) Dust
(d) Vacuum

Correct Answer: (b) Air pollutant

Solution:Any substance, whether solid, liquid, or gas, present in the air in concentrations that are harmful to human health, animal health, vegetation, or materials, is termed an air pollutant.

35. Which of the following is usually not an air-pollutant? [S.S.C. Online Graduate Level (T-I) 2.09.2016 (Shift-II) ]

(a) Hydrocarbons
(b) Sulphur dioxide
(c) Carbon dioxide
(d) Nitrous oxide

Correct Answer: (d) Nitrous oxide

Solution:Nitrous oxide (N₂O) is not generally a pollutant gas, but some benefits are also obtained from its use in appropriate amounts. it has some benefits-

Dentists use it on a dental patient to achieve a painless condition in dentistry.
When a person breathes in an environment containing nitrous oxide, he feels happiness and relaxation. For this reason, it is also called laughing gas.

36. Which of the following fuels causes minimum environmental pollution? [S.S.C. Online Graduate Level (T-I) 2.09.2016 (Shift-II) ]

(a) Diesel
(b) Kerosene
(c) Hydrogen
(d) Coal

Correct Answer: (c) Hydrogen

Solution:Hydrogen gas burns in the presence of oxygen to form only water. This becomes clear from the following equation

2H₂ + O₂ → 2H₂O + energy

But when the above action is carried out in air instead of pure oxygen, some amount of nitrogen oxides are also produced along with the water vapor. Hence it can be concluded that hydrogen is the least polluting gas.

37. The most serious air pollutant causing health hazard is- [S.S.C. Online Graduate Level (T-I) 27.08.2016 (Shift-III) ]

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

Correct Answer: (b) Carbon monoxide

Solution:Carbon monoxide ( $CO$ ): It is a colorless, odorless, and tasteless gas produced by the incomplete combustion of carbon-containing fuels. CO is extremely dangerous because it binds to hemoglobin in red blood cells much more readily than oxygen, forming carboxyhemoglobin. This reduces the blood's ability to carry oxygen to tissues and organs, leading to oxygen starvation. Even at low concentrations, it can cause headaches, dizziness, nausea, and fatigue. At higher concentrations, it can lead to unconsciousness, brain damage, and death very quickly.

38. Which of the following is a cause of pollution of water resources? [S.S.C. JE Mechanical Exam 22.03.2021 (Shift-I) ]

(a) Dead aquatic animals
(b) Dead aquatic plants
(c) Radioactive substances
(d) Deforestation

Correct Answer: (c) Radioactive substances

Solution:Radioactive substances are the cause of pollution of water resources. The substances which keep on generating energy on their own are called radioactive substances. Their radiation is in the form of alpha, beta, gamma, and electron.

This type of radiation from nuclear waste is extremely harmful to organisms, as it causes mutations at a very high rate. Radio sensitivity was discovered by the French scientist Henri Becquerel.

Pollution is caused by human activities such as nuclear power plants, nuclear weapons testing, and the construction and use of radioactive sources. The Government of India passed the Prevention and Control of Water Pollution Act in the year 1974 to save our water resources from getting polluted.

39. The least preferred technique in the disposal of Municipal Solid Waste is- [S.S.C. Online Graduate Level (T-I) 29.08.2016 (Shift-II) ]

(a) Incineration
(b) Composting
(c) Land filling
(d) Briquetting

Correct Answer: (d) Briquetting

Solution:Waste management varies from region to region for a number of reasons, including the type of waste material, the use of the surrounding land, and the area available. Techniques like incineration, composting, landfilling, etc. are generally used by the municipality, but the briquetting technique is the least preferred.

40. During which of the following operating conditions of an automobile, carbon monoxide content in exhaust gas is maximum? [S.S.C. Online Graduate Level (T-I) 2.09.2016 (Shift-I) ]

(a) Acceleration
(b) Cruising
(c) Idle running
(d) Deacceleration

Correct Answer: (c) Idle running

Solution:Idle running: When an engine is idling (e.g., at a stoplight), it operates at a very low RPM and low load. The air-to-fuel ratio can become "rich" (more fuel than optimal for complete combustion), and the exhaust gas temperature might be lower than during active driving. Catalytic converters, which reduce CO emissions, are less efficient at lower temperatures. This combination of factors often leads to the highest concentration of carbon monoxide in the exhaust during idle conditions.

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