Types of Chemical Reactions

During any chemical reaction, there is a conversion of the reactants into a single or many products. A reactant means a substance or substances that are involved in a chemical reaction. The chemical reactions occur under the appropriate conditions of pressure and temperature in the presence of a catalyst. The catalyst plays a significant role in increasing the rate of a chemical reaction without actually getting involved in that reaction.

Types of chemical reactions are characterized by the type of chemical changes. Any chemical reaction yields a single or more products, which are quite different from the reactants. The chemical reactions include some changes that involve the motion of electrons during the formation and breakage of chemical bonds. The chemical reactions could be written in a symbolic form. Chemical equations are used to describe a chemical transformation of elementary particles, which takes place during the reaction. The chemical reactions involve a change in energy; either released or absorbed. Chemical reactions are described as exothermic reactions (in which energy is released) or endothermic reactions (in which energy is absorbed).

Chemical Reactions: Types

There are 6 basic types of chemical reactions such as synthesis reaction, decomposition reaction, single replacement reaction, double replacement reaction, combustion reaction and acid-base reaction.

• Synthesis Reaction: In this reaction, two or more simple substances (reactants) combine together to yield a more complex substance. For example, hydrogen gas combines with oxygen to form a more complex product, water. The chemical equation of this reaction looks as follows:
  2H₂ + O₂ = 2H₂O
• Decomposition Reaction: In this type of chemical reaction, a complex substance breaks down into some simple substances. A single reactant produces two or more products. For example, a water molecule can be broken down into hydrogen and oxygen. This chemical reaction can be presented as:
  2H₂O = 2H₂+ O₂
• Single Replacement or Displacement Reaction: In this kind of reaction, a less active element is replaced by a more active element present in a compound. Two reactants produce two products. For example, when zinc reacts with hydrochloric acid, hydrogen molecule is replaced by zinc to form ZnCl2. This reaction looks like:
  Zn + 2HCL = ZnCl₂ + H₂
• Double Replacement or Displacement Reaction: In this chemical reaction, the cations and anions of two different substances switch their places to yield two totally different compounds. For example, when silver nitrate reacts with sodium chloride, sodium and silver switch their places and there is a formation of sodium nitrate and silver chloride. The chemical equation of this reaction is:
  AgNO₃ + NaCl = AgCl + NaNO₃
• Combustion: During this chemical reaction, a hydrocarbon is burnt in the presence of oxygen to form carbon dioxide (in complete combustion), or carbon monoxide (in partial combustion due to a limited amount of oxygen). This reaction can be presented as:
  C₁₀H₈ + 12O₂ = 10CO₂ + 4H₂O
• Acid-base Reaction: It is a special type of double displacement reaction, which is characterized by the reaction between an acid and a base. In this chemical reaction, H⁺ ion in the acid reacts with OH^- ion present in the base, leading to formation of water. Generally, the end products of this reaction are water and some ionic salts. For example, hydrobromic acid reacts with sodium hydroxide to yield water and NaBr. The equation of this chemical reaction is:
  HBr + NaOH = NaBr + H₂O

Other types of chemical reactions include organic reactions, which involve the compounds having carbon as the major element. Some basic types of organic chemical reactions are addition reaction, redox reaction, elimination reaction, rearrangement reaction, pericyclic reaction and substitution reaction.