Class 10th ## Chemistry ## Chapter-- Chemical Reaction and Equation

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Chapter - Chemical Reaction and Equation
• Chemical Reaction :- When a substance creates one or more new substances by acting alone or any other infinite, then that process is called chemical reaction. Such as:- sodium + chlorine ⟶ sodium chloride Note:- The substances which make new substances by participating in chemical reactions are called reactant and the new substance made after the reaction is called product. H2 + Cl2 ⟶ 2HCL (reactant) (product ) • Chemical equation:- A brief representation of that reaction with the help of signs and formulas participating in a chemical reaction is called chemical equation. H2 + Cl2 ⟶ 2HCL Cao2 + CO2 ⟶ CaCO3 # Different types of chemical reactions 1. Combination reaction / synthesis reaction 2. Decomposition reaction 3. Single Displacement Reaction / Substitution Reaction 4. Double -displacement reaction 5. Precipitation Reaction 6. Neutralization reaction 7. photo chemical reaction 8. Exothermic Reaction 9. Endothermic reaction 1. Combination reaction / Synthesis reaction: - Such a chemical reaction by which two substances or more than two substances combine to form a new substance is called combination reaction. For example :- 2Mg + O2 → 2 MgO H2 + Cl2 → 2HCl 2. Decomposition reaction :- Such a chemical reaction by which a substance decomposes to form two or more substances is called decomposition reaction. eg :- MgCO3 → MgO + CO2 2KClO3 → 2KCl + 3O2 3. Single displacement reaction: - Such a chemical reaction by which a more active element displaces another less active element from a compound and thus forms a new compound, is called a single displacement reaction. For example :- Fe + CuSO4 → FeSO4 + Cu Zn + FeSO4 → ZnSO4 + Fe 4. Double displacement reaction:- Such a chemical reaction by which two reactants exchange their radicals to form two new substances is called double displacement reaction. eg :- AgNO3 + NaCl → AgCl + NaNO3 KOH + H2SO4 → K2SO4 + 2H2O 5. Precipitation reaction: - Such a chemical reaction by which two different substances react in the form of solution and change their radicals to form two new substances. One of which remains in the form of an insoluble precipitate, it is called a precipitation reaction. eg :- BaCl2 + H2SO4 → BaSO4⬇ + 2HCl AgNO3 + HCl → AgC ⬇ + HNO3 6. Neutralization reaction: - Such a chemical reaction by which acid and base change their radicals to form salt and water, it is called neutralization reaction. Example: NaOH + HCl → NaCl + H2O KOH + H2SO4 → K2SO4 + 2H2O 7. Photochemical reaction: - Such chemical reaction which occurs by absorption of light is called photochemical reaction. Example :- 6CO2 + 6H2O → C6H12O6( Glycose ) + 6O2 + 8. Exothermic reaction:- Such a chemical reaction by which heat is emitted is called exothermic reaction. Example :- C + O2 → CO2 + 395KJ S + O2 → SO2 + 297KJ 9. Endothermic reaction:- Such a chemical reaction by which heat is absorbed is called endothermic reaction. Example :- N2 + O2 → 2NO - 180KJ C + 2S → CS2 - 63KJ *** • What is Oxidation? Answer :- Such a chemical reaction by which the number of atoms of oxygen or any other electronegative element in an element or compound increases or their addition is called oxidation reaction. For example :- 2Mg + O2 → 2MgO 2Al + 3Cl2 → 2AlCl3 • What is reduction? Answer :- Such chemical reactions by which the number of atoms of hydrogen or any other electropositive element in an element or compound increases or their addition is called a reduction reaction. For example :- H2 + Cl2 → 2HCl Na + Cl2 → 2NaCl2 • What is rancidity? Answer :- Due to the process of oxidation in the foods made of fat and oil, the action of distasteful smell and taste is called rancidity. • What is corrosion? Answer :- Corrosion is an oxidation-reduction reaction. By which a metal reacts with the air and moisture of the atmosphere and turns into a precipitated substance. For example :- 4Fe + 3H2O + 3O2 → Fe2O3 + 2Fe(OH)3 • What is the solution to avoid corrosion? Answer :- Following are the measures to avoid corrosion. (i) By coating it with any corrodible metal like lead, tin, chromium, etc. (ii) By coating the metal with paint or grease. (iii) By converting iron into stainless steel. • Write the limits of the chemical equation :** Answer :- Following are the limitations of chemical equation. (i) The physical state of the reactants and products are not known from the chemical equation. (ii) The heat released or absorbed as a result of the reaction is not known from the chemical equation. (iii) The chemical equation does not tell the direction of the reaction. (iv) Chemical equation does not provide any information regarding velocity. (v) Quantities of reactants and products are not known from chemical equation.

Chapter - Chemical Reaction and Equation

• Chemical Reaction :- When a substance creates one or more new substances by acting alone or any other infinite, then that process is called chemical reaction.
Such as:- sodium + chlorine ⟶ sodium chloride

Note:- The substances which make new substances by participating in chemical reactions are called reactant and the new substance made after the reaction is called product.
H2 + Cl2 ⟶ 2HCL
(reactant) (product )

• Chemical equation:- A brief representation of that reaction with the help of signs and formulas participating in a chemical reaction is called chemical equation.
H2 + Cl2 ⟶ 2HCL
Cao2 + CO2 ⟶ CaCO3

# Different types of chemical reactions
1. Combination reaction / synthesis reaction
2. Decomposition reaction
3. Single Displacement Reaction / Substitution Reaction
4. Double -displacement reaction
5. Precipitation Reaction
6. Neutralization reaction
7. photo chemical reaction
8. Exothermic Reaction
9. Endothermic reaction

**

1. Combination reaction / Synthesis reaction: - Such a chemical reaction by which two substances or more than two substances combine to form a new substance is called combination reaction.

For example :- 2Mg + O2 → 2 MgO

H2 + Cl2 → 2HCl

2. Decomposition reaction :- Such a chemical reaction by which a substance decomposes to form two or more substances is called decomposition reaction.

eg :- MgCO3 → MgO + CO2

2KClO3 → 2KCl + 3O2

3. Single displacement reaction: - Such a chemical reaction by which a more active element displaces another less active element from a compound and thus forms a new compound, is called a single displacement reaction.

For example :- Fe + CuSO4 → FeSO4 + Cu

Zn + FeSO4 → ZnSO4 + Fe

4. Double displacement reaction:- Such a chemical reaction by which two reactants exchange their radicals to form two new substances is called double displacement reaction.

eg :- AgNO3 + NaCl → AgCl + NaNO3

KOH + H2SO4 → K2SO4 + 2H2O

5. Precipitation reaction: - Such a chemical reaction by which two different substances react in the form of solution and change their radicals to form two new substances. One of which remains in the form of an insoluble precipitate, it is called a precipitation reaction.

eg :- BaCl2 + H2SO4 → BaSO4⬇ + 2HCl

AgNO3 + HCl → AgC ⬇ + HNO3

6. Neutralization reaction: - Such a chemical reaction by which acid and base change their radicals to form salt and water, it is called neutralization reaction.

Example: NaOH + HCl → NaCl + H2O

KOH + H2SO4 → K2SO4 + 2H2O

7. Photochemical reaction: - Such chemical reaction which occurs by absorption of light is called photochemical reaction.

Example :- 6CO2 + 6H2O → C6H12O6( Glycose ) + 6O2 +

8. Exothermic reaction:- Such a chemical reaction by which heat is emitted is called exothermic reaction.

Example :- C + O2 → CO2 + 395KJ

S + O2 → SO2 + 297KJ

9. Endothermic reaction:- Such a chemical reaction by which heat is absorbed is called endothermic reaction.

Example :- N2 + O2 → 2NO - 180KJ

C + 2S → CS2 - 63KJ

***

• What is Oxidation?

Answer :- Such a chemical reaction by which the number of atoms of oxygen or any other electronegative element in an element or compound increases or their addition is called oxidation reaction.

For example :- 2Mg + O2 → 2MgO

2Al + 3Cl2 → 2AlCl3

• What is reduction?

Answer :- Such chemical reactions by which the number of atoms of hydrogen or any other electropositive element in an element or compound increases or their addition is called a reduction reaction.

For example :- H2 + Cl2 → 2HCl

Na + Cl2 → 2NaCl2

• What is rancidity?

Answer :- Due to the process of oxidation in the foods made of fat and oil, the action of distasteful smell and taste is called rancidity.

• What is corrosion?

Answer :- Corrosion is an oxidation-reduction reaction. By which a metal reacts with the air and moisture of the atmosphere and turns into a precipitated substance.

For example :- 4Fe + 3H2O + 3O2 → Fe2O3 + 2Fe(OH)3

• What is the solution to avoid corrosion?

Answer :- Following are the measures to avoid corrosion.

(i) By coating it with any corrodible metal like lead, tin, chromium, etc.

(ii) By coating the metal with paint or grease.

(iii) By converting iron into stainless steel.

• Write the limits of the chemical equation :

Answer :- Following are the limitations of chemical equation.

(i) The physical state of the reactants and products are not known from the chemical equation.

(ii) The heat released or absorbed as a result of the reaction is not known from the chemical equation.

(iii) The chemical equation does not tell the direction of the reaction.

(iv) Chemical equation does not provide any information regarding velocity.

(v) Quantities of reactants and products are not known from chemical equation.

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