Chemical reactions happen almost everywhere. We always relate chemical reactions to the laboratory and test tubes, but the labs can’t control the chemical reactions. The forest fire, iron rusting, and the ripening of fruit all are the part of chemical reactions. Chemical reactions are an integral part of culture, life, and technology. Chemical reactions are quite different from physical changes. Physical changes refer to change in the state. If any physical changes occur, the state of the object gets changed, but the chemical composition remains the same.
In a chemical reaction, the substance that reacts is known as reactants, and the result is known as products. The chemical reactions involve the motion of electrons and breaking or formation of chemical bonds. There are a variety of chemical reactions, and below are some common types of chemical reactions:
Combination
A combination reaction takes place when two or more reactants form a single product. It is also known as the synthesis reaction. The reactants A and B form a single product AB, which is always compound. Depending on the condition or amount of reactants, more than one product can form.
E.g.: 2Na(s)+Cl2(g) 2NaCl(s)
Another such example is the burning of coal:
C(s)+O2(g) CO2(g)
Decomposition
A decombination reaction takes place when a compound breaks down into two or more simpler substances. The reactions are the opposite of a combination reaction. The decomposition reaction needs energy sources like heat, electricity, and light to break the bond.
E.g., Water molecule breaks to form Hydrogen and Oxygen
Single displacement
Single displacement reaction takes place when a more active element displaces another less active element from a compound.
E.g.: Zn(s)+CuSO4(aq) ZnSO4(aq)+Cu(s)
Here, the notation aq shows that the compound is dissolved in water. The zinc replaces copper because it is more reactive than copper.
Double displacement
In a double displacement reaction, two species are displaced. As a by-product, an insoluble solid or water is formed. It is also known as a metathesis reaction. The reaction takes place in a solution, but the end product is either insoluble or water.
Combustion
A combustion reaction takes place when a carbon-containing compound combines with the oxygen in the air. The process is generally known as burning. The most useful product formed is heat.
E.g.: C3H8(g)+5O (g) 3 CO2(g)+4 H2O(1)
Redox
Redox reaction takes place when electrons are exchanged. Redox reactions include combustion, rusting, photosynthesis, and respiration. Another name for the reaction is an oxidation-reduction reaction.
E.g.: 2 Na(s) + Cl2(g) 2 NaCl(s)
