Write the definition of different types …

Chemical reactions can be classified in following types: Combination Reaction Decomposition Reaction Displacement Reaction Double Displacement Reaction Oxidation and Reduction Reaction Combination Reaction: Reactions in which two or more reactants combine to form one product are called COMBINATION REACTION. A general combination reaction can be represented by the chemical equation given here. A + B ⇨ AB Example: When magnesium is burnt in air (oxygen), magnesium oxide is formed. In this reaction, magnesium is combined with oxygen. Mg + O2 ⇨ 2MgO Magnesium + Oxygen ⇨ Magnesium oxide When carbon is burnt in oxygen (air), carbon dioxide is formed. In this reaction, carbon is combined with oxygen. C + O2 ⇨ CO2 Carbon + Oxygen ⇨ Carbon dioxide When hydrogen reacts with chlorine, hydrogen chloride is formed. H2 + Cl2 ⇨ 2HCl Hydrogen + Chlorine ⇨ Hydrogen chloride When calcium oxide reacts with water, calcium hydroxide is formed CaO + H2O ⇨ Ca(OH)2 Calcium oxide + Water ⇨ Calcium hydroxide When carbon monoxide reacts with oxygen, carbon dioxide is formed. 2CO + O2 ⇨ 2CO2 Carbon monoxide + Oxygen ⇨ Carbon dioxide Decomposition Reaction: Reactions in which one compound decomposes in two or more compounds or element are known as DECOMPOSITION REACTION. Decomposition reaction is just opposite of combination reaction. A general decomposition reaction can be represented as follows: AB ⇨ A + B Example: When calcium carbonate is heated, it decomposes into calcium oxide and carbon dioxide CaCO3 ⇨ CaO + CO2 Calcium carbonate ⇨ Calcium oxide + Carbon dioxide When ferric hydroxide is heated, it decomposes into ferric oxide and water 2Fe(OH)3 ⇨ Fe2O3 + 3H2O Ferric hydroxide ⇨ Ferric oxide + Water When lead nitrate is heated, it decomposes into lead oxide, nitrogen dioxide and oxygen. 2Pb(NO3)2 ⇨ 2PbO + 4NO2 + O2 Lead nitrate ⇨ Lead oxide + Nitrogen oxide + Oxygen In above examples, compound is decomposed because of heating, so, these reactions are called THERMAL DECOMPOSITION REACTION.

Chemical reactions can be classified in following types:

• Combination Reaction
• Decomposition Reaction
• Displacement Reaction
• Double Displacement Reaction
• Oxidation and Reduction Reaction

Combination Reaction: Reactions in which two or more reactants combine to form one product are called COMBINATION REACTION.

A general combination reaction can be represented by the chemical equation given here.

<i>A + B ⇨ AB</i>

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Example: When magnesium is burnt in air (oxygen), magnesium oxide is formed. In this reaction, magnesium is combined with oxygen.

<i>Mg + O₂ ⇨ 2MgO</i>

<i>Magnesium + Oxygen ⇨ Magnesium oxide</i>

When carbon is burnt in oxygen (air), carbon dioxide is formed. In this reaction, carbon is combined with oxygen.

<i>C + O₂ ⇨ CO₂</i>

<i>Carbon + Oxygen ⇨ Carbon dioxide</i>

When hydrogen reacts with chlorine, hydrogen chloride is formed.

<i>H₂ + Cl₂ ⇨ 2HCl</i>

<i>Hydrogen + Chlorine ⇨ Hydrogen chloride</i>

When calcium oxide reacts with water, calcium hydroxide is formed

<i>CaO + H₂O ⇨ Ca(OH)₂</i>

<i>Calcium oxide + Water ⇨ Calcium hydroxide</i>

When carbon monoxide reacts with oxygen, carbon dioxide is formed.

<i>2CO + O₂ ⇨ 2CO₂</i>

<i>Carbon monoxide + Oxygen ⇨ Carbon dioxide</i>

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Decomposition Reaction: Reactions in which one compound decomposes in two or more compounds or element are known as DECOMPOSITION REACTION. Decomposition reaction is just opposite of combination reaction.

A general decomposition reaction can be represented as follows:

<i>AB ⇨ A + B</i>

Example: When calcium carbonate is heated, it decomposes into calcium oxide and carbon dioxide

<i>CaCO₃ ⇨ CaO + CO₂</i>

<i>Calcium carbonate ⇨ Calcium oxide + Carbon dioxide</i>

When ferric hydroxide is heated, it decomposes into ferric oxide and water

<i>2Fe(OH)₃ ⇨ Fe₂O₃ + 3H₂O</i>

<i>Ferric hydroxide ⇨ Ferric oxide + Water</i>

When lead nitrate is heated, it decomposes into lead oxide, nitrogen dioxide and oxygen.

<i>2Pb(NO₃)₂ ⇨ 2PbO + 4NO₂ + O₂</i>

<i>Lead nitrate ⇨ Lead oxide + Nitrogen oxide + Oxygen</i>

In above examples, compound is decomposed because of heating, so, these reactions are called THERMAL DECOMPOSITION REACTION.