# Types of Chemical Reactions

Everything is the result of chemical reactions whether you cry or burn wood or dissolve sugar. No process is possible without any chemical reactions occurring in them. Chemical reactions are the basis of each and every activity going on around us. Although there are innumerable activities that involve a chemical reaction, there are certain universal reactions that occur in them. Want to know what types of chemical reactions occur in nature?

Here is this article I have mentioned all types of chemical reactions that form the basis of everything that happens around us.

Before knowing the types of chemical reactions, you must know what exactly is a chemical reaction.

## Definition of Chemical Reaction

According to the definition, a chemical reaction is a process in which reactants react to form products.

Let me explain in simple words; You want to cook food, the vegetables you add to the pan are reactants and the cooked food you get is the product and the changes that took place in the whole process is a chemical reaction.

## Types of Chemical Reactions

### Synthesis or Combination Reactions

The name speaks it all. Synthesis in simple words means the formation of something. When two more elements or compounds react to form a different compound then that process is known as Synthesis.

It is also known as a combination reaction because here the reactants combine to form products.

A + B → AB

You will get it more clearly through the following examples-

$$2Na + Cl_2 → 2NaCl$$

$$H + Cl → HCl$$

In the above examples, Sodium combines with Chlorine to give Sodium Chloride that is a common salt. the equation is then balanced as per the rules of stoichiometry so as to satisfy the law of conservation of matter. Same is with the other example.

### Decomposition Chemical Reactions

Decomposition means to break into simpler and smaller forms. In a decomposition reaction, the larger molecule breaks to give small molecules as products.

AB → A + B

Let me explain to you through examples-

$$CaCO_3 → CaO + CO_2$$

$$2H_2O → 2H_2 + O_2$$

In the given examples, you might have noticed the breakdown of larger substances into smaller substances like Calcium carbonate in the first example and the Electrolysis of water in the second one, hence the name decomposition reaction.

### Substitution and Single Replacement Reactions

In this type of chemical reaction, the more reactive element replaces the less reactive element from its aqueous salt solution to form a new product. I will give you a very easy explanation, suppose you and I are best friends and the third person comes, replaces you and becomes my best friend leaving you alone. From this, you can say the one element is substituted or its place is taken by the other element.

A+ BC → AB+ C

Try to understand with the following chemical reactions:

$$Zn + CuSO_4 → ZnSO_4 + Cu$$

$$Zn + 2 HCl → ZnCl_2 + H_2$$

In both these cases, a more reactive element displaces a less reactive element because of its high affinity to react. Being more reactive in both cases has displaced the individual elements from their respective compounds.

### Double Displacement Reaction or Metathesis

The reactions in which ions are exchanged between the molecules of the reactants are called double displacement reactions. In this, different types of compounds are formed. In layman language you can consider it like you swap your best friend with the other person’s best friend.

AB + CD → AD + CB

For example:

$$NaCl + AgNO_3 → NaNO_3 + AgCl$$

In the given example Sodium and Silver have exchanged their places forming Sodium Nitrate and Silver Chloride respectively. In other words, you can say that there is a swap between Na and Ag.

Also see: Unimolecular Chemical Reactions

### Combustion

Combustion is a type of chemical reaction in which a substance is oxidized with oxygen to form an oxidized compound and heat. These types of reactions are always exothermic. In simple words, you can say that a substance is burnt in the presence of oxygen to give out oxidized product and heat. Remember, in the combustion of a hydrocarbon the products are always carbon dioxide and water.

For example:

$$CH_4 + 2O_2 → CO_2 + 2H_2O + \textrm{heat}$$

The above example shows that methane undergoes combustion to form carbon dioxide, water and heat.

### Acid-Base Neutralisation reaction

As the name suggests neutralization, in this chemical reaction an acid and base react to form salt and water. I will give you one most common example in which a strong acid and a strong base react to form neutralisation products that are salt plus water.

$$HCl + NaOH → NaCl + H_2O$$

### Precipitation reaction

Precipitation reactions are generally characterised by the formation of a precipitate. These reactions involve reactants reacting to giving insoluble salt. The reactants are generally liquid. The precipitate formed is separated from the solution as an indicator of the product formed as result of the chemical reaction.

$$NaCl + AgNO_3 → AgCl \ (\ \textrm{white ppt} \ ) + NaNO_3$$

In the given example the precipitate formed is Silver Chloride which is distinguished from the solution as white precipitate.

### Redox Reactions

Redox is made of two words: Reduction and Oxidation. These types of reactions involve the reduction of one compound and simultaneous oxidation of the other compound. The substance which loses electrons in the whole process is said to be oxidised while the one who gains electrons is reduced. Example:

$${2S_2O_3^2}- +I_2 → {S_4O_6^2}^- +2I^-$$

## Conclusion

So this was all about the types of chemical reactions that occur in most of the processes. I hope this article will help you distinguish between the types of chemical reactions. Just read and try to understand the basic differences between them and take your chemistry to next level. Happy Learning!

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### 1 comment add your comment

1. Hey Gaurav Tiwari ,

Awesome and well-written post. I really like the way you have
explained each types of chemical reactions along with their
examples. As this post is really providing good understanding and
will undoubtedly help readers in understanding the major difference
between the types of chemical reactions.

After going through this complete guide i really got helpful information and according to me this is a perfect guide to know
about various chemical reaction types.

Eventually thanks for sharing your knowledge and such an informative post.

Regards
-Aadarsh

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