Skip to main content

Electrolysis of potassium iodide solution


Filter paper soaked in potassium iodide solution which also contains starch and phenolphthalein is placed on an aluminium sheet which forms one electrode of an electric circuit. The other electrode is used as a ‘pen nib’ to ‘write’ on the filter paper. When this electrode is made positive and the aluminium sheet negative, the writing is blue/black and when the polarity is reversed, the writing is pink.



Hands-on practical activities or ideas for front of class demonstrations


Visit our website for more information on the RSC's Chemistry for Non-Specialists CPD courses.