One More Way to Determine Iron Ions in the Solution

In my recent posts I've wrote about iron compounds. Here's one more post about how to determine iron(III) ions in the solution.

In the photo you can see a diluted iron(III) chloride solution.

Into this solution I've added a few drops of ethanolic solution of salicylic acid (which is colorless).

After stiring this solution all of the solution became purple.

The purple color of the solution is the sign that there are iron(III) ions. These iron(III) ions forms a stable complex compound with salicylic acid. This complex makes the solution purple. If there aren't any iron(III) ions, nothing will happen.