Reaction #6 - Colour change

Hi all,

I have decided to share a colour changing experiment with you. If you have seen us doing experiments in class after PSLE, the experiment you have seen is this one.

For the benefit of those who haven't done so, I shall put it down here.

Step 1 - Dissolve copper sulfate and sodium chloride (more commonly known as table salt) in separate test tubes.

Step 2 - Add the copper sulfate solution to the sodium chloride solution, drop by drop. You will see the copper sulfate solution turning from blue to green! Why is that so?

The answer is simple - copper sulfate and sodium chloride react to form copper(II) chloride and sodium sulfate. Sodium sulfate is colourless while copper(II) chloride is green, making the solution green overall.

Copper sulfate + Sodium chloride → Copper(II) chloride + Sodium sulfate
CuSO₄ + 2 NaCl → CuCl₂ + Na₂SO₄

Hope you've enjoyed reading it!

Reaction by YOSF