WBBSE Solutions For Class 8 School Science Chapter 3 Some Common Gases Review Questions

Chapter 3 Some Common Gases MCQs

Question 1. The following is used as a catalyst during the preparation of oxygen from potassium chlorate

  1. Phosphorous pentoxide
  2. Manganese dioxide
  3. Potassium permanganate
  4. Vanadium pentoxide

Answer: 2. Manganese dioxide

Question 2. Hydrogen acts as an oxidising agent when it

  1. Burns in presence of O2
  2. Forms ammonia when it reacts with nitrogen
  3. Passes through boiling sulphur and forms [h2s]
  4. 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

  1. Hydrogen
  2. Oxygen
  3. CO2
  4. Producer gas

Answer: 1. Hydrogen

Question 4. Na202 is

  1. A basic oxide
  2. A peroxide
  3. An acidic oxide
  4. An amphoteric oxide

Answer: 2. A peroxide

Question 5. Hydrogen is

  1. Completely insoluble in water
  2. Sparingly soluble in water
  3. Completely soluble in water
  4. None of these

Answer: 2. Sparingly soluble in water

Question 6. Air is heavier than hydrogen by

  1. 1.44 times
  2. 14.4 times
  3. 144 Times
  4. Is of equal weight

Answer: 2. 14.4 times

Question 7. O2 And h2 prepared in the laboratory can be collected by

  1. Downward displacement of air
  2. Upward displacement of water
  3. Upward displacement of air
  4. Downward displacement of water

Answer: 4. Downward displacement of water

Question 8. An example of an acidic oxide is

  1. Co
  2. MgO
  3. SO2
  4. Zno

Answer: 3. SO2

Question 9. Hydrogen is adsorbed on

  1. Palladium
  2. Sulphur
  3. Iron
  4. Zinc

Answer: 1. Palladium

Question 10. Oxygen is produced at room temperature due to a reaction between

  1. Sodium peroxide and water
  2. Potassium chlorate and MnO2
  3. Cupric oxide and hydrogen
  4. Potassium chlorate with water

Answer: 1. Sodium peroxide and water

Question 11. Oxygen gas

  1. Is very heavy compared to the air
  2. Slightly heavier than air
  3. Lighter than air
  4. Has equal weight to air

Answer: 2. Slightly heavier than air

Question 12. Oxygen is produced during

  1. Respiration
  2. Photosynthesis
  3. Combustion
  4. Fermentation

Answer: 2. Photosynthesis

Question 13. A balloon is filled up with hydrogen gas.

  1. It will lie on the floor
  2. It will go upwards and will touch the roof of the room in which the experiment is carried out.
  3. It will float in the air
  4. 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

  1. Deep brown
  2. Faint blue
  3. Faint brown
  4. Colourless

Answer: 2. Faint blue

Question 15. Oxygen is absorbed by

  1. Potassium chlorate
  2. Alkaline potassium pyrogallate solution
  3. Potassium permanganate solution
  4. Asbestos

Answer: 2. Alkaline potassium pyrogallate solution

Question 16. The gas which is used together with hydrogen to produce flame and produce a temperature as high as 2800°c is

  1. Nitrogen
  2. Oxygen
  3. Acetylene
  4. 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

  1. Ca
  2. S
  3. C
  4. 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

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.

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 other.
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

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

 

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