Question

What is the definition of three types of chemical reactions?

Answer 1

Hint : A chemical reaction occurs when one or more substances, known as reactants, are converted into one or more different substances, known as products. Chemical elements or compounds are examples of substances. It rearranges the atoms of the reactants' constituents to produce various products.

Complete Step By Step Answer:
There are primarily $5$ types of chemical reactions –
Combination reaction: A chemical reaction that is classified as a combination reaction is a wide category of chemical reactions. Under the right conditions, it can be characterized as a chemical reaction in which two or more substances combine to form a single substance. Since new compounds are synthesized in combination reactions, they are also known as synthesis.
The general formula for this type of reaction is given below –
If A and B are two reactants, then on reactions, it forms product AB
$A + B \to AB$
Ex - $2Na + C{l_2} \to 2NaCl$
Decomposition reaction: A decomposition reaction occurs when a single compound breaks down into two or more simpler compounds. This type of reaction is just opposite to the combination reaction.
The general formula for this reaction is given below –
$AB \to A + B$
Ex - $CaC{O_3} \to CaO + C{O_2}$
Displacement Reaction: A chemical reaction that occurs when a more reactive element displaces a less reactive element from its aqueous salt solution. Another name of this reaction is Substitution reaction.
The general formula for this reaction is given below –
$A + BC \to AB + C$
Ex - $Zn + CuS{O_4} \to ZnS{O_4} + Cu$
Double Displacement Reaction: A double displacement reaction is a chemical reaction in which ions are exchanged between two reactants to form a new compound. Another name for this reaction is metathesis reaction.
The general formula for this reaction is given below –
$XY + ZA \to XZ + YA$
Ex - $BaC{l_2} + N{a_2}S{O_4} \to BaS{O_4} + 2NaCl$
Precipitation Reaction: Precipitation reaction is a chemical reaction that results in the formation of an insoluble substance (precipitate; solid). Although the reactants are soluble, the resulting product is insoluble and separates as a solid.
Ex - $NaCl(aq) + AgN{O_3}(aq) \to AgCl(s) + NaN{O_3}(aq)$
You can take any of the three reaction from the above according to the given question.

Note :
Precipitation reaction occurs when a solution containing dissolved species releases a solid that is normally denser and falls to the bottom of the reaction vessel.