cleaning keyboards in the dishwasher

On 1/9/2006 at 11:20 PM C Fernandez wrote: Just what I wrote earlier. Aluminum, zinc and magnesium all react with hot water to form a hydroxide, liberating hydrogen as a reaction product. The reason your aluminum pots don't dissolve when you boil water in them is because aluminum (and zinc and magnesium) form a thin, very tough layer of oxide which seals the metal suface from the action of the water. One of the classic freshman chemistry demonstrations is (or was) to immerse a piece of aluminum under a pool of mercury, with hot water poured on top. The aluminum has its layer of oxide removed with a bit of sandpaper and when the metal is raised out of the mercury into contact with the hot water, it reacts with the water, producing bubbles of hydrogen gas. This is also why one doesn't put out a magnesium fire with water, by the way. When a moderately strong base (such as sodium phosphate or sodium carbonate) is hydrolized in hot water, the basic solution attacks the oxide on the surface of the metal, forming a soluble salt, exposing the underlying metal to the action of the water. If the base is very strong, such as lye, the water needn't even be hot; which is how good old Drano works (nothing more than lye and aluminum granules); the reaction produces enough heat, which coupled with the action of the now-hot lye acts on grease and protein to clear blockages. All of which goes to saying why you shouldn't put aluminum, magnesium or zinc (including galvanized hardware) in your dishwasher with dishwashing detergent. Cheers, Chuck