krit.club logo

Chemical Reactions and Equations - TYPES OF CHEMIC1.2 TYPES OF CHEMIC1.2 TYPES OF CHEMIC1.2 TYPES OF CHEMIC1.2 TYPES OF CHEMIC AL REA AL REAAL REA AL REAAL REA CTIONS CTIONSCTIONSCTIONSCTIONS

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

A Combination Reaction is a reaction where two or more reactants combine to form a single product, such as the reaction of quicklime with water: CaO(s)+H2O(l)→Ca(OH)2(aq)CaO(s) + H_{2}O(l) \rightarrow Ca(OH)_{2}(aq).

•

A Decomposition Reaction involves a single reactant breaking down into two or more simpler products. This requires energy in the form of heat (Thermal), light (Photolytic), or electricity (Electrolytic).

•

In a Displacement Reaction, a more reactive element displaces a less reactive element from its compound, e.g., Fe(s)+CuSO4(aq)→FeSO4(aq)+Cu(s)Fe(s) + CuSO_{4}(aq) \rightarrow FeSO_{4}(aq) + Cu(s).

•

Double Displacement Reactions involve an exchange of ions between the reactants to form new compounds, often resulting in the formation of an insoluble substance called a Precipitate.

•

Exothermic Reactions are those in which heat is released along with the products, while Endothermic Reactions are those in which energy is absorbed.

•

Redox Reactions (Oxidation-Reduction) occur when one reactant gets oxidized (gains oxygen or loses hydrogen) while the other gets reduced (loses oxygen or gains hydrogen) simultaneously.

📐Formulae

A+B→AB(Combination)A + B \rightarrow AB \quad \text{(Combination)}

AB→EnergyA+B(Decomposition)AB \xrightarrow{\text{Energy}} A + B \quad \text{(Decomposition)}

2FeSO4(s)→ΔFe2O3(s)+SO2(g)+SO3(g)2FeSO_{4}(s) \xrightarrow{\Delta} Fe_{2}O_{3}(s) + SO_{2}(g) + SO_{3}(g)平衡

2H2O(l)→Electrolysis2H2(g)+O2(g)2H_{2}O(l) \xrightarrow{\text{Electrolysis}} 2H_{2}(g) + O_{2}(g)平衡

A+BC→AC+B(Displacement)A + BC \rightarrow AC + B \quad \text{(Displacement)}

AB+CD→AD+CB(Double Displacement)AB + CD \rightarrow AD + CB \quad \text{(Double Displacement)}

ZnO+C→Zn+CO(Redox)ZnO + C \rightarrow Zn + CO \quad \text{(Redox)}

💡Examples

Problem 1:

What happens when silver chloride is exposed to sunlight? Write the balanced chemical equation and identify the type of reaction.

Solution:

2AgCl(s)→Sunlight2Ag(s)+Cl2(g)2AgCl(s) \xrightarrow{\text{Sunlight}} 2Ag(s) + Cl_{2}(g) This is a Photolytic Decomposition Reaction.

Explanation:

White silver chloride turns grey in sunlight due to the decomposition of silver chloride into silver metal and chlorine gas.

Problem 2:

Identify the substance oxidized and the substance reduced in the following reaction: CuO(s)+H2(g)→ΔCu(s)+H2O(g)CuO(s) + H_{2}(g) \xrightarrow{\Delta} Cu(s) + H_{2}O(g)平衡

Solution:

Substance Oxidized: H2H_{2} (to H2OH_{2}O); Substance Reduced: CuOCuO (to CuCu).

Explanation:

CuOCuO loses oxygen, which is reduction. H2H_{2} gains oxygen, which is oxidation. Since both occur, it is a Redox reaction.

Problem 3:

When a solution of sodium sulfate is added to a solution of barium chloride, a white precipitate is formed. Write the balanced equation.

Solution:

Na2SO4(aq)+BaCl2(aq)→BaSO4(s)↓+2NaCl(aq)Na_{2}SO_{4}(aq) + BaCl_{2}(aq) \rightarrow BaSO_{4}(s) \downarrow + 2NaCl(aq)

Explanation:

This is a double displacement reaction where Ba2+Ba^{2+} and SO42−SO_{4}^{2-} ions react to form the white precipitate of Barium Sulfate (BaSO4BaSO_{4}).