With hot concentrated sulphuric acid
When hot concentrated sulphuric acid is added to sulphur it oxidises to sulphur dioxide. During the reaction sulphuric acid undergoes thermal decomposition and in the process water, sulphur dioxide and nascent oxygen are formed.
Nascent oxygen reacts with sulphur to form additional sulphur dioxide.
OR
With hot concentrated nitric acid
Hot concentrated nitric acid oxidises sulphur to sulphuric acid.
Sulphur is further oxidised by the nascent oxygen to sulphur trioxide.
Sulphur trioxide then combines with water to form sulphuric acid.
OR
