ELECTROLYSIS OF SILVER NITRATE SOLUTION

Mike Clark

Toowoomba, Australia


This demonstration is very pretty to watch, and can be manipulated to showhow small changes in the physical conditions of an electrolysis can affectthe physical properties of the products of the reactions. It is conductedunder a microscope, so is useful only where microscopes are available.Alternatively, if a video hook-up from a microscope is available, the reactionscould be displayed to good effect on video.

 

It can be quite fiddly to set up, and may require some practice before goodobservations can be obtained.

 

A solution of silver nitrate contains silver ions and nitrate ions, as wellas hydrogen and hydroxide ions from the aqueous solvent. Silver is a ratherunreactive metal, so it might be expected that silver ions will be reducedand precipitated as metallic silver at the cathode. What cannot be predictedwithout experiment is the appearance of the crystals of silver metal thatforms. At an inert platinum anode, two oxidations are possible: hydroxideto oxygen, and/or silver(I) to silver(III). Both oxidations can be observed.Spectacular results occur when conditions favour production of silver(III).

 

MATERIALS REQUIRED

SETTING UP THE DEMONSTRATION

OBSERVATIONS

INTERPRETATION