Question

Formation of $S{{O}_{3}}$ from $S{{O}_{2}}$ and ${{O}_{2}}$ is a ________ reaction.

Answer 1

Any reaction consists of the substances called as reactants that react with each other to produce gases, or liquids and solids as products. There are various types of reactions like, combination, decomposition, displacement, and double- displacement reactions.

Complete answer:
There are various types of reactions in chemistry. Some of them are combination reactions, decomposition reactions, displacement reactions and double- displacement reactions, neutralization reactions, etc.
Among them, whenever two reactants react to carry out a reaction and form a single product, then it is called a combination reaction. We have given that $S{{O}_{3}}$is formed from the reaction between$S{{O}_{2}}$and${{O}_{2}}$. The reaction is as follows:
$2S{{O}_{2}}+{{O}_{2}}\to 2S{{O}_{3}}$
As in this reaction we can see that two reactants sulphur dioxide, and oxygen molecule, react to form a single product which is sulphur trioxide, so this reaction is a type of a combination reaction.
Hence, formation of $S{{O}_{3}}$from $S{{O}_{2}}$and ${{O}_{2}}$ is a combination reaction.

Additional information:
This combination reaction is an important reaction in the manufacture of sulphuric acid. Also acid rain is the result of this reaction happening in the outer atmosphere, where oxygen reacts with $S{{O}_{x}}$ gases which are pollutants to form acid rain that has traces of acid and can tarnish the monuments and buildings made of marble.

Note:
The reaction in which 2 reactants combine is the combination reaction, while when a single substance decomposes in the presence of heat, then more that one product is forms which is called the decomposition reaction, and is the opposite of combination reaction, for example, $2{{H}_{2}}O\to 2{{H}_{2}}+{{O}_{2}}$.