A Short Note on Types of Chemical Reactions

Chemical reactions are the processes that lead to the production of new compounds with unique characteristics. Environmental changes result from chemical reactions. During chemical reactions, atoms are rearranged between reacting components, leading to the production of new molecules with fundamentally different features.

Chemical reactions entail the breaking of odd chemical bonds between atoms of reacting substances, followed by the production of new chemical bonds between the rearranged atoms of new substances. During a chemical reaction, atoms of one element do not exchange places with atoms of another. A chemical reaction is the rearranging of atoms.

Properties exhibited by a chemical reaction

The following are some of the properties of chemical reactions:

• The combination of 2 or above molecules leading to the generation of a fresh element is called a chemical reaction (s).
• Reactants are compounds which combine among themselves to generate a new chemical. Product refers to the chemicals generated as a result of the reactant interaction.
• The chemical change in a chemical interaction should occur within the tangible change taking place in the outcome, such as heat evolution, colour change, etc.
• A chemical reactivity may occur between particles, and they produce a new link by breaking previous ones, with no atom disintegration or generation but resulting in the formation of something new.
• The degree of change in a reaction is affected by several parameters, including pressure, temperature, and concentration value of the reactant.

Types of Chemical Reactions

A chemical reaction is a process defined by a chemical change in which the initial elements (reactants) differ from the resultant elements. Chemical reactions are characterised by the movement of electrons, which results in the creation and dissolution of chemical bonds. There are various types of chemical reactions and they can be classified in more than one way. Here are a few common reactions:

Oxidation-Reduction or Redox Reaction

Oxidation is the whole or partial loss of electrons or the acquisition of oxygen. Reduction is the entire or partial gain of electrons or the loss of oxygen. A redox reaction is another word for an oxidation-reduction process.

The oxidation numbers of atoms are altered during a redox process. Electrons can be transferred between chemical species during redox reactions.

Example: –

2 S2O32−(aq) + I2(aq) → S4O62−(aq) + 2 I−(aq)

One example of a redox reaction is the process that happens when I2 is reduced to I– and S2O32- (thiosulfate anion) is oxidised to S4O62-.

Direct Combination or Synthesis Reaction

In a direct combination or synthesis reaction, two or more chemical species unite to generate a more complex product.

X + Y → XY

Example: –

The reaction of iron with sulphur to produce iron (II) sulphide

8 Fe + S8 → 8 FeS

Chemical Decomposition or Analysis Reaction

A decomposition reaction occurs when a more complex material decomposes into its simpler constituents. Certain energy changes in the environment, such as heat, light, or electricity, must be made in order to break the bonds of the molecule.

AB → A + B

Example

The electrolysis of water into oxygen and hydrogen gas 

2 H2O → 2 H2 + O2

Single Displacement or Substitution Reaction

One element is displaced from a compound by another element in a substitution or single displacement process. Products can be identified in these reactions by reactivity series. It is a series in which the components are organised in diminishing order of reactivity. The elements placed at the topmost of the series have more reactivity than the components at the lowermost of this series.

 A + BC → AC + B

Example

 Zn + 2 HCl → ZnCl2 + H2

In this reaction, the hydrogen is replaced by Zinc.

Metathesis or Double Displacement Reaction

In a double displacement or metathesis process, two chemicals swap bonds or ions to generate new molecules. It is a kind of chemical interaction where 2 chemical elements react and their ions, and swap positions, resulting in the formation of two entirely separate items.

 AB + CD → AD + CB

Example

NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)

The above reaction between sodium chloride and silver nitrate leads to the formation of sodium nitrate and silver chloride.

Acid-Base/Neutralisation Reaction

An acid-base reaction is a sort of double displacement reaction that happens when an acid and a base come into contact. The acid’s H+ ion combines with the base’s OH– ion to generate water and an ionic salt.

HA + BOH → H2O + BA

Example –

The reaction that takes place between the aqueous solution of hydrogen bromide (HBr) and caustic soda 

(HBr) + (NaOH) → NaBr + H2O

Conclusion

New substances are produced during a chemical reaction. For this to happen, the chemical bonds of the substances break, and the atoms that make up the substances split and reorganise themselves into new substances with new chemical bonds. This is referred to as a chemical reaction when it occurs. A chemical reaction is a process by which one or more chemicals are converted into one or more new ones.