Chemical Reactions and their Types – Maharashtra Board Class 8 Solutions for General Science

Chemical Reactions and their Types- Maharashtra Board Class 8 Solutions for General Science (English Medium)

MathematicsGeneral ScienceMaharashtra Board Solutions

Solution 1.a

Different types of chemical reactions are

1. Combination reaction
2. Decomposition/dissociation reaction
3. Displacement reaction

Solution 1.b

A chemical reaction in which a single compound is formed from two or more reactants is called a combination reaction, whereas a reaction in which a substance is broken down and two or more substances are formed is called a dissociation reaction.
In a combination reaction, only one product is formed.
In a decomposition reaction, two or more products are formed.

Solution 1.c

A chemical reaction in which oxygen combines with an element or compound or a reaction in which hydrogen is lost from a compound is called an oxidation reaction.
Example:
C + O₂ → CO₂

Solution 1.d

A chemical reaction in which hydrogen combines with an element or compound or a reaction in which oxygen is lost from a compound is called a reduction reaction.
Example:
Cl₂ + H₂ → 2HCl

Solution 1.e

A substance which does not take part in a chemical reaction but by its presence speeds up a chemical reaction is called a catalyst.

Solution 1.f

Factors on which the speed of chemical reactions depends:

1. Size of reactant particles
2. Temperature
3. Concentration
4. Presence of catalyst

Solution 2

1. Combination reaction (Exothermic reaction)
2. Oxidation reaction (Combination reaction, Exothermic reaction)
3. Reduction reaction (Combination reaction)
4. Combination reaction (Combination reaction, Oxidation reaction)

Solution 3

Solution 4

‘A’	‘B’
a. Reduction	2. Combining with hydrogen
b. Oxidation	4. Combination with oxygen
c. Displacement	1. Type of chemical reaction
d. Catalyst	3. Speeding up a reaction