RRB NTPC 2025 Science MCQ Series 1, Answer All Most Important Questions Now

RRB NTPC 2025 Science MCQ Series 1: The RRB NTPC (Railway Recruitment Board Non-Technical Popular Categories) exam is a highly competitive examination for candidates aspiring to work in various non-technical positions in Indian Railways. General Studies (GS) is one of the key sections of the exam, encompassing a wide range of topics such as current affairs, history, geography, general science, economics, and more.

In this MCQ Series 1, we have compiled some of the most important and frequently asked questions that are likely to appear in the RRB NTPC GS section. By practicing these questions, candidates can strengthen their knowledge and improve their preparation for the exam. These questions cover a variety of topics, helping aspirants to revise and test their understanding of the core concepts that are essential for the RRB NTPC General Studies section.

RRB NTPC 2025 Science MCQ Series 1

1. Why is Carbon Dioxide (CO₂) gas filled in cold drinks?

• a) It increases the sweetness
• b) It reacts with water to form carbonic compounds
• c) It adds color to the drink
• d) It acts as a preservative

2. Which gas is an allotrope of oxygen?

• a) Ozone
• b) Carbon dioxide
• c) Nitrogen
• d) Argon

3. The most common unit for measuring ozone concentration is:

• a) Pascal
• b) Dobson unit
• c) Atmosphere
• d) Mole

4. What prevents ultraviolet rays from reaching the Earth?

• a) Carbon dioxide
• b) Ozone layer
• c) Nitrogen
• d) Water vapor

5. What is causing the depletion of the ozone layer?

• a) Methane
• b) Chlorofluorocarbons (CFCs)
• c) Carbon monoxide
• d) Nitrogen oxides

6. Which gas is emitted from refrigerators and air conditioners?

• a) Nitrous oxide
• b) Chlorofluorocarbons (CFCs)
• c) Carbon monoxide
• d) Ammonia

7. What is commonly referred to as laughing gas?

• a) Nitrogen
• b) Carbon dioxide
• c) Nitrous oxide (N₂O)
• d) Helium

8. What is another name for Freon?

• a) Nitrogen gas
• b) Chlorofluorocarbons (CFCs)
• c) Ozone
• d) Carbon monoxide

9. What is the primary use of CFCs?

• a) Food preservatives
• b) Insecticides
• c) Refrigerants and aerosol propellants
• d) Fertilizers

10. Which poisonous gas was used in World War II?

• a) Sarin
• b) Chlorine
• c) Lewisite
• d) Hydrogen cyanide

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11. What is the name of tear gas?

• a) Ammonia
• b) Chloropicrin (CCl₃NO₂)
• c) Hydrogen chloride
• d) Mustard gas

12. Which gases are responsible for acid rain?

• a) Carbon dioxide and nitrogen oxides
• b) Sulfur dioxide, nitrogen dioxide, and carbon monoxide
• c) Oxygen and ozone
• d) Hydrogen and methane

13. In which process does one gas mix with another gas due to differences in density?

• a) Evaporation
• b) Diffusion
• c) Sublimation
• d) Condensation

14. The diffusion properties of gases increase with the increase in:

• a) Pressure
• b) Temperature
• c) Density
• d) Volume

15. Compared to solids and liquids, gases are:

• a) Less compressible
• b) Highly compressible
• c) Incompressible
• d) Not affected by pressure

16. Under what conditions does a gas condense?

• a) High pressure and low temperature
• b) Low pressure and high temperature
• c) Low pressure and low temperature
• d) High pressure and high temperature

17. What is the rate of diffusion of a gas?

• a) The volume it occupies
• b) The amount of gas that expands in unit time
• c) The pressure it exerts
• d) The temperature of the gas

18. According to Graham’s law of diffusion, the rate of expansion of gases is inversely proportional to:

• a) The square root of its temperature
• b) The square root of its density or molar mass
• c) The square of its pressure
• d) Its volume

19. According to Avogadro’s Law, the number of molecules in a given volume of gas at NTP is:

• a) Proportional to the pressure
• b) Proportional to the temperature
• c) The same for all gases
• d) Inversely proportional to the volume

20. Boyle’s Law states that the pressure of a fixed quantity of gas at constant temperature is:

• a) Directly proportional to its volume
• b) Inversely proportional to its volume
• c) Inversely proportional to its temperature
• d) Unaffected by the volume

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Answers to the RRB NTPC 2025 Science MCQ Series 1

Here are the answers to the RRB NTPC GS MCQ Series 1:

1. b) Inversely proportional to its volume
2. b) It reacts with water to form carbonic compounds
3. a) Ozone
4. b) Dobson unit
5. b) Ozone layer
6. b) Chlorofluorocarbons (CFCs)
7. b) Chlorofluorocarbons (CFCs)
8. c) Nitrous oxide (N₂O)
9. b) Chlorofluorocarbons (CFCs)
10. c) Refrigerants and aerosol propellants
11. c) Lewisite
12. b) Chloropicrin (CCl₃NO₂)
13. b) Sulfur dioxide, nitrogen dioxide, and carbon monoxide
14. b) Diffusion
15. b) Temperature
16. b) Highly compressible
17. a) High pressure and low temperature
18. b) The amount of gas that expands in unit time
19. b) The square root of its density or molar mass
20. c) The same for all gases

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