The correct procedure of heating iron-sulphur mixture to prepare iron sulphide is :

Compare the properties of iron (II) sulphide with iron-sulphur mixture, considering iron sulphide as a compound & particles of iron & sulphur mixed together as an example of a mixture,

Four students (A),(B),(C) and (D) observed the colour and solubility of iron, sulphur and iron, sulphur and iron sulphide in carbon disulphide. The tick mark represents soluble and cross mark represents insoluble, in carbon disulphide. Their observation are tabulated below The student who correctly reported the observations, is student :

Iron + sulphur to Iron(II) sulphide

Iron is not present in the form of sulphide in:

Write the formula of Iron(II) sulphide.