Question

Kunal took few iron turnings and mixed them well with Sulphur powder. He could separate the iron turnings with the help of a magnet. He heated the mixture for some time and tried to separate the iron turnings with the magnet but he could not. Why?

• A. On heating, a chemical change takes place and a new compound is formed.
• B. On heating, iron becomes non-magnetic hence, it is not attracted by magnet.
• C. On heating, a physical change takes place hence iron and Sulphur gets mixed up.
• D. On heating, iron evaporates and only sulphur is left behind

Answer 1

The correct option is A On heating, a chemical change takes place and a new compound is formed.

$Fe+S\stackrel{Heat}{\to }FeS$

Iron Iron Sulphide

On heating iron and Sulphur, a new substance, iron sulphide is formed, so it is a chemical change.

Hence the correct option is A.