Question

8. Define with examples.

a) Decomposition reaction.

b) Double Displacement reaction

c) Redox reaction ft​

Answer 1

Question :

Define with examples

• a) Decomposition reaction
• b) Double Displacement reaction
• c) Redox reaction

ANSWER

Decomposition reaction : -

A reaction in which a single compound divides/splits into 2 or more compounds when some external energy is supplied is called Decomposition reaction.

Represented as;

AB -----> A + B

Depending upon the externally energy supplied the reactions are of 3 types;

• Thermal Decomposition reaction
• Electrolytic Decomposition reaction
• Photo/Photo chemical Decomposition reaction

A reaction in which heat is evolved is generally termed as Exothermic reaction.

( Here, exo means releasing out)

Similarly,

A reaction in which heat is absorbed is generally

termed as Endothermic reaction.

( Here, endo means absorption)

Examples for Decomposition reaction;

1.

$\sf{ CaCO_3 \xrightarrow{heat \Delta} \quad CaO + CO_2}$

2.

$\sf{ 2H_20 \xrightarrow{electricity} \quad 2H_2 + O_2 }$

3.

$\sf{ 2AgBr \xrightarrow{sunlight} \quad 2Ag + Br_2 }$

Double Displacement reaction : -

A reaction in which there is an exchange of ions between 2 radicals is called as Double Displacement reaction. In a double displacement reaction 2 new compounds will be formed.

Represented as;

AB + CD ----> AC + BD

These are of 2 types;

• Precipitation reaction
• Neutralising reaction

Examples;

1.

$\sf{NaSO_4 + BaCl \rightarrow BaSO_4 + NaCl}$

2.

$\sf{ AgNO_3 + NaCl \rightarrow AgCl + BaNO_3}$

Redox reaction : -

A redox reaction is a chemical reaction in which in there is an exchange of electrons among the reactants.

Generally, in this reaction the oxygen is removed when we add hydrogen to the compound.

However,

The word redox means reduction-oxidation.

Reduction : Gain of electrons or Add of hydrogen

Oxidation : Loss of electrons or add of oxygen

Examples;

1.

$\sf{ H_2 + F_2 \rightarrow 2HF }$

2.

$\sf{ MgO +H_2 \rightarrow Mg + H_2O }$

Answer 2

Answer:

a)Decomposition reaction:-

  A compound where it breaks down into two or more compounds.

   ex:- AB=A+B

b)Double Displacement Reaction:-

  A reaction where  the left hand side and right hand side elements are         balanced.

  ex:-AB+C=CB+A

c)Redox Reaction:-

  A redox reaction can be defined as a chemical reaction in which electrons    are transferred between two reactants participating in it.

 ex:-2NaH → 2Na + H2