(English Medium) ICSE Class 9 - CISCE Question Bank Solutions

How many electrons do inert gases have in their valence shells?

Comment on the (i) reactivity (ii) colour (iii) physical state of group 17 elements.

Name the gas used in:

Filling balloons

Name the gas used in:

Light bulbs

Name the gas used in:

Bright colour advertising light works

 Give reason:

Alkali metals are kept in an inert solvent.

 Give reason:

Alkali metals and halogens do not occur free in nature.

 Give reason:

Alkali and alkaline earth metal compounds usually form electrovalent compounds.

 Give reason:

Inert gases do not form compounds.

How will you distinguish between temporary hard water and permanent hard water?

Using given sample of temporary and permanent hard water, soft water, ordinary soap, detergent and washing soda how would you distinguish between temporary hard water and permanent hard water?

Using given sample of temporary and permanent hard water, soft water, ordinary soap, detergent and washing soda how would you remove temporary hardness from water without using a chemical compound?

Using given sample of temporary and permanent hard water, soft water, ordinary soap, detergent and washing soda how would you remove temporary hardness and permanent hardness from water using a chemical compound?

Define the term of mass number.

Define the term of mass number.

Write down the mass number of the atom having 20 neutrons and 15 protons.

Write down the mass number of the atom having 20 neutrons and 15 protons.

What would be the reason for an element to have atoms with different mass numbers?

What would be the reason for an element to have atoms with different mass numbers?

Both temporary & permanent hardness in water can be removed by addition of washing soda. Give balanced equations for the same.