Physical or Chemical Change

Question

When Iron (III) chloride reacts with potassium thiocyanate, the color of the solution changed to red, but no new substance is formed?

So is this a physical or chemical change?

Answer 1

This would definitely be a chemical change. If there is a color change, that suggests that the products of the reaction are chemically different from the reactants. In this case, you have the following reaction:

iron(III) chloride + potassium thiocyanate ==> iron(III) thiocyanate + potassium chloride

FeCl3 + 3KSCN ===> Fe(SCN)3 + 3KCl