The main #types, of #chemical, #reactions,

Chemical reactions can be classified into several main types based on the changes that occur during the reaction. Here are the main types:

1. Synthesis (Combination) Reactions
Definition: Two or more reactants combine to form a single product.
General Form:
𝐴
+
𝐵
→
𝐴
𝐵
A+B→AB
Example:
2
𝐻
2
+
𝑂
2
→
2
𝐻
2
𝑂
2H
2
​
+O
2
​
→2H
2
​
O (formation of water)
2. Decomposition Reactions
Definition: A single compound breaks down into two or more simpler substances.
General Form:
𝐴
𝐵
→
𝐴
+
𝐵
AB→A+B
Example:
2
𝐻
2
𝑂
2
→
2
𝐻
2
𝑂
+
𝑂
2
2H
2
​
O
2
​
→2H
2
​
O+O
2
​
(decomposition of hydrogen peroxide)
3. Single Displacement (Single Replacement) Reactions
Definition: One element replaces another element in a compound.
General Form:
𝐴
+
𝐵
𝐶
→
𝐴
𝐶
+
𝐵
A+BC→AC+B
Example:
𝑍
𝑛
+
2
𝐻
𝐶
𝑙
→
𝑍
𝑛
𝐶
𝑙
2
+
𝐻
2
Zn+2HCl→ZnCl
2
​
+H
2
​
(zinc displacing hydrogen in hydrochloric acid)
4. Double Displacement (Double Replacement) Reactions
Definition: The ions of two compounds exchange places in an aqueous solution to form two new compounds.
General Form:
𝐴
𝐵
+
𝐶
𝐷
→
𝐴
𝐷
+
𝐶
𝐵
AB+CD→AD+CB
Example:
𝐴
𝑔
𝑁
𝑂
3
+
𝑁
𝑎
𝐶
𝑙
→
𝐴
𝑔
𝐶
𝑙
+
𝑁
𝑎
𝑁
𝑂
3
AgNO
3
​
+NaCl→AgCl+NaNO
3
​
(reaction between silver nitrate and sodium chloride)
5. Combustion Reactions
Definition: A substance combines with oxygen, releasing energy in the form of light and heat.
General Form:
𝐶
𝑥
𝐻
𝑦
+
𝑂
2
→
𝐶
𝑂
2
+
𝐻
2
𝑂
C
x
​
H
y
​
+O
2
​
→CO
2
​
+H
2
​
O (for hydrocarbons)
Example:
𝐶
𝐻
4
+
2
𝑂
2
→
𝐶
𝑂
2
+
2
𝐻
2
𝑂
CH
4
​
+2O
2
​
→CO
2
​
+2H
2
​
O (combustion of methane)
6. Redox (Oxidation-Reduction) Reactions
Definition: Reactions that involve the transfer of electrons between reactants, resulting in changes in oxidation states.
General Form: Not fixed, but involves changes in oxidation numbers.
Example:
2
𝑁
𝑎
+
𝐶
𝑙
2
→
2
𝑁
𝑎
𝐶
𝑙
2Na+Cl
2
​
→2NaCl (sodium is oxidized and chlorine is reduced)
7. Acid-Base Reactions (Neutralization)
Definition: An acid reacts with a base to produce a salt and water.
General Form:
𝐻
𝐴
+
𝐵
𝑂
𝐻
→
𝐵
𝐴
+
𝐻
2
𝑂
HA+BOH→BA+H
2
​
O
Example:
𝐻
𝐶
𝑙
+
𝑁
𝑎
𝑂
𝐻
→
𝑁
𝑎
𝐶
𝑙
+
𝐻
2
𝑂
HCl+NaOH→NaCl+H
2
​
O (reaction between hydrochloric acid and sodium hydroxide)
Summary
These are the main types of chemical reactions, each characterized by specific changes in reactants and products. Understanding these types helps in predicting the outcomes of reactions and in balancing chemical equations.
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1. What is Chemical reaction? 1 Definition:    The processes, in which a substance or substances undergo a chemical change to produce new substance or substances, with entire new properties, are known as chemical reactions. The nature and identity of products totally different from the reactants REACTANTS: Compounds that interact to produce new compounds are called reactants PRODUCTS : whereas the newly formed compounds are called products. Chemical reactions play an integral role in different industries, customs and even in our daily life. They are continuously happening in our general surroundings; for example, rusting of iron, pottery, fermentation of wine and so on.

2. 2 Types of chemical reactions

3. Combination (synthesis) reaction Definition: Reaction in which two or more simpler substances (elements) combine chemically to give a compound. + -----------  CaO (s) + H2O(l) ------  Ca(OH)2 ( aq ) + Heat (quick lime) (Slaked lime) Burning of coal C(s) + O2 (g) ---- CO2 (g) Formation of water 2H2 (g) + O2 (g) --- 2H2O (l) Burning of natural gas CH4(g) + 2O2(g) ------ CO2 (g) + O2 (g) Respiration C6H12O6 ( aq ) + 6O2 ( aq ) ------ 6CO2 ( aq ) + 6H2O (l) + energy 3 A B A B

4. Decomposition reaction Definition: A single substance decomposes to give two or more substances -----------  + 2FeSO4(s) -----------  Fe2O3(s) + SO2(g) + SO3(g) (Ferrous sulphate) (Ferric oxide) CaCO3(s) -- ---------- CaO (s) + CO2 (g) 2Pb(NO3)2(s) --------- 2PbO(s) + 4NO2 + O2(g) (Lead nitrate) (lead oxide) (Nitrogen dioxide) (oxygen) 2AgCl(s) ---------- 2Ag(s) + Cl2 (g) 2AgBr (s) --------------- 2Ag (s) + Br2 (g) 4 B A A B

5. 3. Single replacement (Substitution) reaction Definition: Reaction in which element displaces another element from its compound + -----  + or + -------  + Fe(s) + CuSO4( aq ) ---------  FeSO4( aq ) + CU(s) (Copper sulphate) (Iron sulphate) Zn(s) + CuSO4( aq ) -------- ZnSO4( aq ) + Cu(s) Pb(s) + CuCl ( aq ) ------ PbCl2 ( aq ) + Cu(s) 5 B A A B B B A A C C C C

6. 4. Double replacement (Metathesis) (precipitation) Definition: Reaction in which two different atoms or groups of atoms (ions) are exchanged Precipitation reactions produce insoluble salts. + -------  + NaSO4( aq ) + BaCl2( aq ) ----  BaSO4(s) + 2NaCl ( aq ) (Sodium (Barium (Barium (Sodium sulphate) chloride) sulphate) chloride) AgNo3 + NaCl ---- AgCl + NaNO3 6 A D B C C B D A

7. 6 Redox (Reduction- Oxidation) Reaction in which electron transfer occurs. Reduction: is the loss of oxygen or gain of hydrogen. Oxidation: is the gain of oxygen or loss of hydrogen. Oxidation CuO + H2 ---------  Cu + H2O Reduction ZnO + C ----- Zn + CO MnO2 + 4HCl ----- MnCl2 + 2H2O + Cl2 7

8. 5. Neutralization (Acid-Base) Definition: Reaction in which an acid reacts with a base to give salt and water HCl + NaOH ------  NaCl + H2O H2SO4 + 2KOH ----- K2SO4 + 2H2O Combustion Reaction: A combustion is a chemical reaction between a fuel and an oxidant that produces an oxidized product . Usually, it is a reaction between a hydrocarbon and oxygen to yield carbon dioxide, water and heat or light 8 Acid Base Salt Water Acid Salt Base Water

9. Type of Reaction General Reaction Explanation Synthesis or Combination A + B → AB Two or more elements or compounds combine to form one compound. Decomposition or Analysis AB → A + B A complex molecule breaks into simpler ones. Displacement, Replacement, or Substitution A + BC → AC + B One element replaces another in a compound. Double displacement, Double replacement, or Metathesis AB + CD → AD + CB Exchange of cations and anions Reaction in which a solid compound is formed when solutions of two soluble compounds are mixed. xcartners . Combustion A + O 2  → H 2 O + CO 2 A compound combines with oxygen to form an oxide. Often, carbon dioxide and water form.   Neutralization Acid + Base → Salt + Water An acid and base react to form a salt and water. Redox( Oxidation&Reduction ) Electron transfor In which electrons are transferred between reactants. Oxidation: gain of oxygen, loss of hydrogen Reduction: gain of hydrogen, loss of oxygen Example 2 2H2O+O2--  2H2O 2H2O---  2H2 + O2 Zn + HCl --  ZnCl2+H2 AgNO3+NaCl-  AgCl+NaNO3 CH4+O2-- CO2+H2O+Heat and light HCl + NaOH-- NaCl+H2O ZnO2 + C ----- Zn + CO The main types of chemical reactions

10. Worksheet Identify each type of reaction: 1. 2 NaBr + Ca(OH)2 -  CaBr2 + 2 NaOH double displacement 2. 2 NH3+ H2SO4 ---  (NH4)2SO4 synthesis 3. 4 C5H9O + 29 O2 ---  20 CO2 + 18 H2O combustion 4. 3 Pb + 2 H3PO4 ---  3 H2 + Pb3(PO4)2 single displacement 5. Li3N + 3 NH4NO3 --  3 LiNO3 + (NH4)3N double displacement 6. 3 HBr + Al(OH)3 ---  3 H2O + AlBr3 double displacement 7. Na3PO4 + 3 KOH--  3 NaOH + K3PO4 double displacement 8. MgCl2 + Li2CO3--  MgCO3 + 2 LiCl double displacement 9. C6H12 + 9 O2 -----  6 CO2 + 6 H2O combustion 10.Pb + FeSO4 ----  PbSO4 + Fe single displacement 11.CaCO3 ---  CaO + CO2 decomposition 12.P4 + 3 O2 ---  2 P2O3 synthesis 13.2 RbNO3 + BeF2---  Be(NO3)2 + 2 RbF double displacement 14.2 AgNO3 + Cu ---  Cu(NO3)2 + 2 Ag single displacement 15.C3H6O + 4 O2 --  3 CO2 + 3 H2O combustion 16.2 C5H5 + Fe --  Fe(C5H5)2 synthesis 17.SeCl6 + O2 ---  SeO2 + 3Cl2 single displacement 18.2 MgI2 + Mn(SO3)2---  2 MgSO3 + MnI4 double displacement 19.O3 ----  O. + O2 decomposition 20.2 NO2 ---  2 O2 + N2 decomposition 10