English Medium कक्षा ९ - CBSE Question Bank Solutions

Work out the formula for sulphur dioxide. (Valencies : S = 4 ; O = 2)

If the valency of carbon is 4 and that of sulphur is 2, work out the formula of the compound formed by the combination of carbon with sulphur. What is the name of this compound ?

An element X has a valency of 4 whereas  another element Y has a valency of 1. What will be the formula of the compound formed between X and Y ?

An element B shows valencies of 4 and 6. Write the formulae of its two oxides.

An element X of valency 3 combines with another element Y of valency 2. What will be the formula of the compound formed ?

Name the following compounds. Also write the symbols/formulae of the ions present in them :

1. CuSO4
2. (NH4)2SO4
3. Na2O
4. Na2CO3
5. CaCl2

Give the formulae of the compounds formed from the following sets of elements :

1. calcium and fluorine
2. hydrogen and sulphur
3. nitrogen and hydrogen
4. carbon and chlorine
5. sodium and oxygen
6. carbon and oxygen

(a) Write the symbols/formulae of two simple ions and two compound ions (or polyatomic ions).

An element Y has a valency of 4. Write the formula for its :

1. chloride
2. oxide
3. sulphate
4. carbonate
5. nitrate

Define ‘formula unit’ of an ionic compound. What is the formula unit of (i) sodium chloride, and
(ii) magnesium chloride ?

Which of the following represents a correct chemical formula ?

The formula of a compound is X3Y. The valencies of elements X and Y will be respectively :

An element A forms an oxide A₂O₅.

What will be the formula of chloride of A ?

The formula of carbonate of a metal M is M₂CO₃.

What will be the formula of its iodide ?   

The formula of carbonate of a metal M is M₂CO₃.

What will be the formula of its nitride ?

The formula of carbonate of a metal M is M₂CO₃.

 What will be the formula of its phosphate ?

Identify the following substance:

An alkaline gas A which gives dense white fumes with hydrogen chloride.

Identify the following substance:

Gas B that has an offensive smell as of rotten eggs.

Identify the following substance:

Gas C that is colourless and can be used as a bleaching agent.

Identify the following substance:

A brown gas D with the irritating smell.