The violet color obtained in the Lassaigne's test for a sulfur-containing compound is due to the formation of which species?

Lassaigne's test is not used for the detection of the element . . . . . . in the organic compound.

In the qualitative test for the identification of the presence of phosphorus,the compound is heated with an oxidizing agent. It is further treated with nitric acid and ammonium molybdate,respectively. The yellow-coloured precipitate obtained is:

Which of the products indicates the presence of sulphur atom in an organic compound,in qualitative elemental analysis?

Given below are two statements:
Statement $I$ : Sulphanilic acid gives esterification test for carboxyl group.
Statement $II$ : Sulphanilic acid gives red colour in Lassaigne's test for extra element detection.
In the light of the above statements,choose the most appropriate answer from the options given below :

Lassaigne’s test is used to detect which of the following elements in an organic compound?