Nitu mixed some iron filings with sulphur powder in a China dish. She heated the contents of China dish. What did she observe during the experiment?

Options

A. There was no difference in the contents of China dish before and after heating.
B. Before heating, iron filings and sulphur powder could be seen separately but after heating the contents became black.
C. Before heating, the iron filings and sulphur powder could not be seen separately.
D. Before heating, the contents were black and after heating, iron filings and sulphur could be seen separately.

Answer

B

Explanation

On heating, iron reacts with sulphur to form black solid of iron sulphide. This is an irreversible, chemical change.