Which of the following is not a property of air?

a. Air is a colourless mixture of gases. b. Air occupies space. c. Air is translucent.

Experiments conducted by which of the following scientists proved that air is a mixture of number of substances?

Air is a mixture of a number of substances. Which of the following is not a component of air?

Which of the following statements is/are false?

a. The amount of water vapour present in air is not a fixed quantity, but varies with the change in weather. b. Everything on the surface of the Earth is surrounded by an envelope of air. c. A few of the underwater living organisms can survive without air.

Which of the following statements is/are false?

a. Air always contains suspended particles that may be dust, smoke or any other material. b. The presence of dust particles in air never varies from place to place and time to time. c. Air always contains some amount of water vapours.

Which of the following components of air supports combustion?

Air is a mixture of gases. Which of the following are its two major components?

a. Oxygen b. Carbon dioxide c. Nitrogen d. Helium

Which of the following is the reason due to which the visibility increases after rains?

Air is a mixture of various gases of different densities. Which among the following is the lightest gas in air, in terms of density?

Which of the following statements is/are false?

a. Gases like carbon dioxide, helium and water vapours constitute the major volume of air. b. The fine hair and mucus within the nasal passage prevents the dust particles from getting into the respiratory system. c. Air is necessary for the burning of any substance.

Which of the following statements is/are false?

a. The process by which oxygen reacts with the digested food to form carbon dioxide, water vapour and heat energy is called respiration. b. Charcoal burns in air to produce carbon monoxide. c. Tall chimneys in factories carry harmful gases to the upper layers of air and prevent pollution of air to some extent.

Mountaineers carry oxygen cylinders on high altitudes because

Which of the following component of air is used for making fertiliser needed for agriculture?

Which of the following gas is useful for plants in making their food through the process of photosynthesis?

Which of the following statements is/are false?

a. There is a drop in temperature and pressure of the air with the increase in height. b. The air becomes thinner and thinner as one go high up in the atmosphere. c. The gases in the atmosphere are stationary and help in the formation of weather.