Question

A gas formed by burning sulphur in air is _________.
A. sulphur dioxide
B. ammonia
C. hydrogen sulphide
D. chlorine

Answer 1

Hint: The gas formed from sulphur when it is subjected to combustion must have sulphur as a component in the process. After the reaction the gases responsible for combustion will be involved in the reaction and hence, they also form a component in the resultant product formed at the end of combustion.

Complete answer:
Combustion of any specific compound or element occurs in the presence of oxygen. Oxygen is the specific gas which is most important for combustion because it facilitates the process by oxidising the element or the compound which is undergoing combustion. This is the way in which burning or combustion takes place resulting in the production of energy.
In the process of combustion, when sulphur is burned it reacts with the oxygen present in the air. Therefore, after the burning of the sulphur is completed the resultant product which is formed contains the residues like sulphur and oxygen. The compound that is formed due to burning is sulphur dioxide. This means oxygen is trapped along with sulphur in the form of a compound.
Therefore, the resultant reaction when sulphur is subjected to burning will be:
$S + {O_2} \to S{O_2}$
This is an exothermic process resulting in the release of energy during burning and a high temperature of more than ${1000^o}C$.

Hence, option A is correct.

Note:
Burning of any specific compound produces energy as the liberation of energy occurs during this oxidation process. The high temperature is reached in the system due to the burning process and the heat changes.