Question

Sulphur when burnt in air forms __________

Answer 1

We need to know that the sulphur is a chemical compound having the atomic number $16$ with chemical symbol S. It is a multivalent element. The trivalent sulphur contains three positive charges and it is known as sulfonium ion. If three different alkyl groups are attached with sulphur atoms, the sulfonium ion has a stereogenic center. It shows the extended valency from $- 1$ to $+ 6$. That is, the maximum valency of sulphur is equal to six.

Complete answer:
When the sulphur burns with air in the presence of oxygen there is a formation of a gas which is known as sulphur dioxide. This sulphur dioxide is acidic in nature. And the reaction can be written as,
$S + {O_2} \to S{O_2}$
Here, one mole of sulphur is reacting with one mole of oxygen to form one mole of sulphur dioxide. And this reaction takes place by the oxidation reaction. Because, if a substance loses hydrogen or gains oxygen during a reaction, that is known as oxidation. Here, the sulphur atom gains the oxygen and there is a formation of sulphur dioxide. Hence, this is an oxidation reaction.

Note:
We need to know that when sulphur is burnt in air it forms sulphur dioxide. And it is a toxic gas. The hybridization of sulphur dioxide is $s{p^2}$ with bond angle $119^\circ$ and it has a bent shape or V – shape. And here the sulphur is surrounded with two oxygen atoms. The sulphur contains one lone pair of electrons. The electron geometry of sulphur dioxide is trigonal planar. The number of valence electrons of both oxygen and sulphur is six and it is polar in nature due to its electronegativity difference between $S$ and $O$ atoms.