WBBSE Chapter 3 Some Common Gases MCQs
Question 1. The following is used as a catalyst during the preparation of oxygen from potassium chlorate
- Phosphorous pentoxide
- Manganese dioxide
- Potassium permanganate
- Vanadium pentoxide
Answer: 2. Manganese dioxide
Question 2. Hydrogen acts as an oxidising agent when it
- Burns in presence of O2
- Forms ammonia when it reacts with nitrogen
- Passes through boiling sulphur and forms [h2s]
- Reacts with metals to form metallic hydrides.
Answer: 2. Forms ammonia when it reacts with nitrogen
Read And Learn More WBBSE Solutions For Class 8 School Science Review Questions
Question 3. The gas which is used for the hardening of oil and fat is
- Hydrogen
- Oxygen
- CO2
- Producer gas
Answer: 1. Hydrogen
Question 4. Na202 is
- A basic oxide
- A peroxide
- An acidic oxide
- An amphoteric oxide
Answer: 2. A peroxide
WBBSE Class 8 Science Chapter 3 Review Questions
Question 5. Hydrogen is
- Completely insoluble in water
- Sparingly soluble in water
- Completely soluble in water
- None of these
Answer: 2. Sparingly soluble in water
Question 6. Air is heavier than hydrogen by
- 1.44 times
- 14.4 times
- 144 Times
- Is of equal weight
Answer: 2. 14.4 times
Question 7. O2 And h2 prepared in the laboratory can be collected by
- Downward displacement of air
- Upward displacement of water
- Upward displacement of air
- Downward displacement of water
Answer: 4. Downward displacement of water
Question 8. An example of an acidic oxide is
- Co
- MgO
- SO2
- Zno
Answer: 3. SO2
Question 9. Hydrogen is adsorbed on
- Palladium
- Sulphur
- Iron
- Zinc
Answer: 1. Palladium
WBBSE Science Chapter 3 Important Questions
Question 10. Oxygen is produced at room temperature due to a reaction between
- Sodium peroxide and water
- Potassium chlorate and MnO2
- Cupric oxide and hydrogen
- Potassium chlorate with water
Answer: 1. Sodium peroxide and water
Question 11. Oxygen gas
- Is very heavy compared to the air
- Slightly heavier than air
- Lighter than air
- Has equal weight to air
Answer: 2. Slightly heavier than air
Question 12. Oxygen is produced during
- Respiration
- Photosynthesis
- Combustion
- Fermentation
Answer: 2. Photosynthesis
Question 13. A balloon is filled up with hydrogen gas.
- It will lie on the floor
- It will go upwards and will touch the roof of the room in which the experiment is carried out.
- It will float in the air
- It will catch fire
Answer: 2. It will go upwards and will touch the roof of the room in which the experiment is carried out.
Question 14. The colour of liquid oxygen is
- Deep brown
- Faint blue
- Faint brown
- Colourless
Answer: 2. Faint blue
Question 15. Oxygen is absorbed by
- Potassium chlorate
- Alkaline potassium pyrogallate solution
- Potassium permanganate solution
- Asbestos
Answer: 2. Alkaline potassium pyrogallate solution
Class 8 Science Gases Review Answers
Question 16. The gas which is used together with hydrogen to produce flame and produce a temperature as high as 2800°c is
- Nitrogen
- Oxygen
- Acetylene
- Carbon monoxide
Answer: 2. Oxygen
Question 17. \(\mathrm{X}+\mathrm{O}_2 \rightarrow \mathrm{Y}, \mathrm{Y}+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{Z}\) If Z turns red litmus to blue, then X may be
- Ca
- S
- C
- P
Answer: 1. Ca
Chapter 3 Some Common Gases Fill In The Blanks
Question 1. About 2500 million years ago a bacteria, called __________ began to split water to form oxygen.
Answer: Cyanobacteria
Question 2. The enzyme __________ found in our body breaks down hydrogen peroxide into water and oxygen.
Answer: Catalase
Question 3. About __________ million years ago, the amount of oxygen reached the present level.
Answer: 500
Question 4. The density of oxygen at normal pressure and temperature is __________ gram per litre.
Answer: 1.428
Question 5. The solubility of oxygen at O°C and 1 atmospheric pressure is __________ mg per litre.
Answer: 14.8
Question 6. The freezing point of liquid oxygen is __________ °C.
Answer: -218
Question 7. The boiling point of liquid oxygen is __________ °C.
Answer: -183
Question 8. At – 183°C, oxygen condenses to form a pale,__________ liquid.
Answer: Bluish
Question 9. When cooled with liquid hydrogen, liquid oxygen gives a __________ coloured solid.
Answer: Blue
Question 10. The oxygen molecule is __________.
Answer: Diatomic
Question 11. Oxygen is non-combustible i.e. it itself does not burn. But it is a__________ of combustion.
Answer: Supporter
Question 12. Oxygen gas is slightly __________ than air.
Answer: Heavier
Question 13. Alkaline __________ solution absorbs oxygen and turns dark brown.
Answer: Potassium pyrogallate
WBBSE Class 8 Science Review Exercises
Question 14. __________ solution absorbs oxygen gas quickly and turns blue.
Answer: Ammonium cuprous chloride
Question 15. During the preparation of oxygen by heating potassium chlorate,__________ is used as a catalyst.
Answer: Manganese dioxide(MnO2)
Question 16. __________ is the lightest element.
Answer: Hydrogen
Question 17. Hydrogen is __________ in water.
Answer: Insoluble
Question 18. Air is about __________ times heavier than hydrogen.
Answer: 14.4
Question 19. __________ gas is the best conductor of heat among all gases.
Answer: Hydrogen
Question 20. __________ adsorbs the largest volume of hydrogen at 0°C.
Answer: Palladium
Question 21. __________ is not a supporter of combustion but it is inflammable.
Answer: Hydrogen
Question 22. __________ is also known as hydrolith.
Answer: Calcium Hydride (CaH2)
Question 23. A gas balloon is filled up with __________gas.
Answer: Hydrogen
Question 24. The density of hydrogen is __________ gram per litre at 0°C and 1-atmosphere pressure.
Answer: 0.0899
Question 25. __________ is an allotrope of oxygen.
Answer: Ozone
Question 26. __________ is a neutral oxide.
Answer: Nitric Oxide (NO)
Question 27. If only potassium chlorate is heated, oxygen gas is produced at a temperature of __________ °C.
Answer: 650
Chapter 3 Some Common Gases Identify as True or False
Question 1. Oxygen is inflammable and not a supporter of combustion.
Answer: False
Question 2. Hydrogen is inflammable and not a supporter of combustion.
Answer: True
Question 3. LED is used as a bulb in a torch because it has a long lifetime.
Answer: True
Question 4. Sulphur dioxide is a basic oxide.
Answer: False
Question 5. Carbon dioxide is an acidic oxide.
Answer: True
Question 6. Water is an amphoteric oxide.
Answer: False
Question 7. Rusting is basically the oxidation of iron metal.
Answer: False
Question 8. Atomic hydrogen is a very good reducing agent.
Answer: True
Question 9. Oxygen is collected in a gas jar by upward displacement of water.
Answer: False
Question 10. A gas balloon is filled up with hydrogen because it is much lighter than air.
Answer: True
Question 11. Nickel can adsorb a maximum volume of hydrogen at 0°C.
Answer: False
Question 12. Oxygen is produced easily when water is added to solid sodium peroxide at room temperature.
Answer: True
Question 13. The enzyme catalase destroys hydrogen peroxide and superoxide ions in our bodies.
Answer: True
Question 14. Round bottom flasks are round bottom, narrow neck glass containers, most suitable when heating of reaction mixture is required during any chemical reaction.
Answer: True
Question 15. Watch glass is like a small, circular, glass plate used for carrying/ testing a small amount of solid or liquid substances.
Answer: True
Question 16. A funnel is used for transferring liquids or solids from one container to the other.
Answer: True
Question 17. A measuring cylinder is used to measure the volume of liquid.
Answer: True
Question 18. Burettes and pipettes are used for transferring a definite volume of liquid from one container to another.
Answer: True
Question 19. Hydrogen gas is highly soluble in water.
Answer: False
Question 20. The respiration of aquatic animals is dependent on the dissolved oxygen in the water.
Answer: True
Question 21. Hydrogen is used for the hardening of fats and oils (where unsaturated fatty acids are converted to saturated compounds which have higher melting points).
Answer: True
Class 8 Science Chapter 3 Question Bank
Question 22. Magnesium oxide is an acidic oxide.
Answer: False
Question 23. Hydrogen is usually prepared in the laboratory by the reaction between dilute HCI or dilute H2S04 with granulated zinc in a Woulfe’s bottle (or a round bottom flask).
Answer: True
Question 24. The interior of the sun contains a very large amount of hydrogen which is continuously converted into helium by a process called fusion, at a very high temperature.
Answer: True
Question 25. For welding and cutting of metals, oxy-hydrogen flame and oxy-acetylene flame are used.
Answer: True
Question 26. Amphoteric oxide undergoes a neutralization reaction with both acids and bases.
Answer: True
Chapter 3 Some Common Gases Match The Columns
1.
Column – A | Column – B |
A. acidic oxide | 1. MgO |
B. basic oxide | 2. SO2 |
C. amphoteric oxide | 3. CO |
D. neutral oxide | 4. ZnO |
Answer: A-2,B-1,C-4,D-3
2.
Column – A | Column – B |
A. liquid oxygen | 1. CaH2 |
B. odourless | 2. Mixture of CO2 and |
C. hydrolith | 3. faint blue coloured |
D. carbogen | 4. hydrogen |
Answer: A-3,B-4,C-1D-2
3.
Column – A | Column – B |
A. cyanogen | 1. oxygen |
B. MnO2 | 2. hydrogen |
C. supporter of combustion | 3. production of oxygen by splitting water |
D. available in trace amount in the atmosphere in a free state | 4. catalyst during the production of oxygen from KCIO |
Answer: A-3,B-4,C-1,D-2