EASY
7th CBSE
IMPORTANT
Earn 100

Arrange the components of air in the increasing order of their percentage by volume.

1) Nitrogen

2) Carbon dioxide

3) Oxygen

4) Argon

12.5% studentsanswered this correctly

Important Questions on Air and Oxygen

EASY
7th CBSE
IMPORTANT
_____ burns in oxygen with a brilliant golden yellow flame.
EASY
7th CBSE
IMPORTANT
Y is obtained by the decomposition of a substance X. Oxygen present in X is univalent. Y reacts with a neutral oxide and evolves Z which is composed of reddish brown fumes which turns moist blue litmus red. Identify X, Y, Z.
HARD
7th CBSE
IMPORTANT

Identify the four layers of atmosphere as per the temperature range mentioned and arrange them in a sequence of -60 °C to -15 °C, 17 °C to-51°C , -15 °C  to -120 °C and maximising up to 2000 °C.

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Exosphere
  5. Thermosphere
HARD
7th CBSE
IMPORTANT
Air is a homogeneous mixture of gases which also contains argon and nitrogen which are used for filling electric bulbs. But air is not filled in electric bulbs because:
HARD
7th CBSE
IMPORTANT

A list of four different substances is given below The methods of preparation of the substances are also given. Arrange the methods of preparation in the order of the substances given. 
(i) O2
(ii) CO2
(iii) SO2
(iv) P2O5 

  1. Burning of a non-metal produces dense white fumes.
  2. Burning of a non-metal with sparkles and crackling sound.
  3. Heating of one of the binary compounds of hydrogen.
  4. Burning of a non-metal with a brilliant blue flame.
EASY
7th CBSE
IMPORTANT
The holes in the ozonosphere is due to the attack of a pollutant that is released from:
HARD
7th CBSE
IMPORTANT
A gas X when passed through blue litmus solution turns it to red. Another gas Y when passed through either blue litmus or red litmus does not change the colour of the litmus. Identify the true statement regarding X and Y.
HARD
7th CBSE
IMPORTANT

Identify the layers of atmosphere as per the activities mentioned and arrange them in a sequence.

Burning up of meteorites, flying of aeroplanes, reflection of radio waves, absorption of harmful ionising radiations and occurrence of most of the weather phenomena.

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Ionosphere
  5. Magnetosphere