ICSE ICSE Class 7 - CISCE Question Bank Solutions

Taking hydrogen peroxide, how would you prepare oxygen in the laboratory ?

What is the role of manganese dioxide in the preparation of oxygen?

Why is oxygen collected by downward displacement of water?

Why is hydrogen peroxide preferred in the preparation of oxygen gas ?

What happens when a glowing splinter is introduced in a jar containing oxygen ?

What happens when oxygen gas is passed through alkaline pyrogallol solution ?

What happens when mercuric oxide is heated?

What happens when potassium nitrate is heated 

Why is potassium chlorate not used for laboratory preparation of oxygen ?

Name the three types of oxidation processes. In which of these large amount of heat and light energy are produced?

What do you observe when Phosphorus is heated and then tested with moist blue and red litmus – paper?

Complete and balance the following chemical equation.

\[\ce{KNO3 ->[heat]KNO2 +}\] _____

Give four uses of oxygen.

How is oxygen naturally renewed in air ?

Fill in the blank :

____________ discovered the oxygen gas.

Fill in the blank :

Oxygen occupies about _____% of air by volume.

The natural way of adding oxygen to air which involves green plants is called

Fill in the blank space by choosing the correct word from the given list.

List: oxygen, carbonic, suIphur dioxide gas, precipitation, helium

Every nine parts of water by weight contains eight parts by weight of _________.

Statement given below is incorrect. Write the correct statement :

The percentage of oxygen in air by volume, varies from 21% to 22%.

Fill in the blank:

Oxygen is slightly _________ than air.