Question

define and explain the types of chemical reaction with any three examples

Answer 1

Explanation:

Types of Chemical Reactions Explanation General Reaction

Combination reaction Two or more compounds combine to form one compound. A + B → AB

Decomposition reaction The opposite of a combination reaction – a complex molecule breaks down to make simpler ones. AB → A + B

Answer 2

$\bf{\large{Answer}}$

Chemical Reaction:- Chemical reactions are the reactions which tranform substances into new ones.

Chemical Reactions are mainly composed of Reactants and Products.

Chemical Reactions are mainly composed of Reactants and Products.Reactants:- The substances which take part in a reaction are known as reactants. They are present on LHS of the arrow.

Products:- These are the new substances formed after a reaction. Ther are present on the RHS of the arrow.

Types of reactions:-

1. Combination Reaction:- The reaction in which two or more substances combine to form a single product is known as Combination Reaction.

$\sf{Eg.:- Ca (s) + H_2O (l) \longrightarrow Ca(OH)_2}$

Most of the combination reactions are exothermic reaction. It is because in most of the combination reactions heat is evolved.

$\sf{\star}$Exothermic Reaction:- The reaction in which heat is evolved is known as Exothermic Reaction.

$\sf{Eg.:- C (s) + O_2 (g) \longrightarrow CO_2 (g) + Heat}$

2. Decomposition Reaction:- The reaction in which one single reactant decomposes to form two or more products is known as Decomposition Reaction.

$\sf{Eg.:- 2Pb(NO_{3})_{2} (s) \xrightarrow{Heat} 2PbO (s) + 4NO_{2} (g) + O_2 (g)}$

Most of the decomposition reactions are endothermic reactions. It is because most of the decompostion reactions absorb heat.

$\sf{\star}$Endothermic Reaction:- The reaction in which heat is absorbed is known as Endothermic Reaction.

$\sf{Eg.:- Fe_{2}SO_{4} (s) \xrightarrow{Heat} Fe_{2}O_{3} + SO_{2}(g) + SO_3(g)}$

3. Displacement Reaction:- The reaction in which a more reactive metal displaces a less reactive metal in a compound is known as Displacement Reaction.

$\sf{Zn(s) + CuSO_4 (aq) \longrightarrow ZnSO_4 (aq) + Cu (s)}$

Some more reactions:-

1. Double Displacement Reaction:- The reaction in which exchange of ions between two compounds to form a new compound takes place is known as Double Displacement Reaction.

$\sf{Eg.:- BaCl_2 (aq) + H_2SO_4 (aq)\longrightarrow BaSO_4 (s) + 2HCl (aq)}$

2. Thermal Decomposition Reaction:- When Decomposition Reaction take place in the presence of heat they are called Thermal Decomposition Reaction.

$\sf{Eg.:- 2Pb(NO_{3})_{2} (s) \xrightarrow{Heat} 2PbO (s) + 4NO_{2} (g) + O_2 (g)}$

3. Photochemical Decomposition:- When decomposition reaction takes place under the sunlight, they are called Photochemical Reaction.

$\sf{Eg.:- 2AgCl (s) \xrightarrow{Sunlight} 2Ag (s) + Cl_2}(g)$

4. Electrolysis:- When substance decomposes by the passage of electricity into it, the reaction is termed as Electrolysis.

$\sf{2H_2O (l) \xrightarrow{Electricity} 2H_2 (g) + O_2 (g)}$