MEDIUM
8th CBSE
IMPORTANT
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Which of the following metals does not react with O2 even at high temperatures?

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Important Questions on Air and Oxygen

HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 45
Which of the following reactions is associated with the formation of a mirror-like surface near the cooler part of the test tube?
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 46
You are asked to prepare oxygen from air after eliminating the impurities in the order, i.e., at first dust particles, then water vapour and CO2 at the end. Based on the given instruction arrange the processes given below in a sequence:
  1. passing the sample of air through concentrated NaOH
  2. repeated compression followed by sudden expansion
  3. fractional distillation of liquefied air
  4. passing the air through electrostatic precipitator
  5. passing the air through anhydrous CaCl2 
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 47
Arrange the following products (oxides) in the ascending order of the ratio of metal atoms to oxygen atom(s) present in one molecule of the respective oxide.
  1. magnesium is heated in the presence of oxygen
  2. iron produces a reddish brown powder with a crackling sound when it is heated at higher temperature
  3. sodium undergoes oxidation in moist air
  4. formation of a coating of aluminium oxide on aluminium at normal temperature 
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 48
The description of the different layers of the atmosphere is given below. Arrange them in the increasing order of their altitude.
  1. the layer of atmosphere in which the number of molecules is less, but they are sufficient to burn the meteorites
  2. the layer in which the temperature increases with attitude
  3. the layer with the least number of particles
  4. the convection current of air plays a significant role in this layer 
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 49
Arrange the products of the following reactions in the increasing order of the number of oxygen atoms associated with one non-metallic atom.
  1. burning of phosphorus in an adequate supply of oxygen to produce an oxide of phosphorus
  2. the complete combustion of coke with the supply of sufficient oxygen
  3. an electric spark is provided to a 1 : 1 mixture of nitrogen and oxygen
  4. burning of sulphur dioxide gas in oxygen
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 50
Arrange the following steps involved in the preparation of oxygen from KClO3 in a proper order.
  1. Content of the test tube is heated
  2. 2. A mixture of finely ground KClO3 and MnO2 is taken in a test tube.
  3. The open end of the test tube is plugged with cotton.
  4. Delivery tube is taken out.
  5. The test tube is fixed in a slanting position.
  6. Bunsen burner is put off.
  7. Oxygen is collected by downward displacement of water.
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 51
What are the advantages of an aneroid barometer over a mercury barometer? Give the applications of the aneroid barometer.
HARD
8th CBSE
IMPORTANT
Pearson IIT Foundation Chemistry>Chapter 4 - Air and Oxygen>PRACTICE QUESTIONS (COMPETITION WING)>Q 52
Why are tin coated iron cans used for cool drinks but not galvanised iron cans? Explain.