Types of redox reaction

 

1. Reactants are substances that take part in a chemical reaction, while products are the new substances produced during the chemical reaction.

 Example,   A+ B → C                       C + O₂ → CO₂

 

2. When two or more elements or compounds react chemically to form one new compound, then the chemical reaction that takes place is a chemical combination reaction.

Example, 2 H₂O → 2H₂ + O₂

3. When a chemical compound decomposes on heating or by some other way so as to form two or more compounds or elements then the reaction that takes place is called chemical decomposition.

Example, X + YZ → XZ + Y

4. When a more active metal or nonmetal displaces a less active element from its aqueous salt solution, the reaction that takes place is called displacement or substitution reaction.

Displacement reaction is of 2 types:-

Example:-  CuSO₄ + Zn → Cu + ZnSO₄

Non-metal Displacement:- It involves hydrogen displacement & rarely occurring oxygen displacement.

Example:- 2 Na + 2H₂O → 2 NaOH + H₂

5. A chemical reaction in which two ionic compounds in their aqueous solutions react by exchanging their ions/radicals to form to two new compounds is called Chemical Double Decomposition.

AB + CD → AD + CB.

6. A Polymerization reaction is one in which two or more molecules (monomers) combine to form a new bigger molecule.

7. Disproportionation reaction:-

It is a specific types of redox reaction in which a species is simultaneously reduced and oxidized to form two different products.

Example:- 3 Cl₂ + 6 OH^- → 5 Cl^- + Clo₃^- + 3 H₂O

Here chlorine gas (Cl₂) has 0 oxidation state, Cl^- has -1 and Clo₃^- has +5.

Here cl is oxidized to Clo₃^-

And cl is reduced to Cl^-.

8. Chemical equations can be made more informative by indicating physical states, heat changes and condition under which the reaction takes place.

• A reaction in which heat is given out is Exothermic. ΔH is negative 

  Reactants = Products + Energy

• A reaction in which heat is taken in is called Endothermic. ΔH is positive.

  Reactants + Energy = Products