Question

on strongly heating a mixture of iron filing and sulphur powder a black mass is formed due to the formation

Answer 1

The reaction of this process is:

$$\mathrm{Fe} + \mathrm{S} = \mathrm{FeS}$$

Iron(II) sulfide or ferrous sulfide (Br.E. sulphide) is a chemical compound with the formula FeS.

It is black color compound.