How does an arrangement with a zinc and brass rods dipped in Na2CO3(aq) restores the shine. What is the purpose of the sodium carbonate.
sry for the looong question..
2006-09-03 14:46:52 · 1 answers · asked by Buzz 1 in Science & Mathematics ➔ Chemistry
The acid residues on the brass causes oxidation. The trick is to get the flux off when it is still hot. I like using a wet cotton rag to wipe off the acid while it is still quite hot - about 250-300F/120-150C. If you time it right, the rag will sizzle a bit, but the solder will have set up - go from mirror shiny to a chalky finish. Then the piece doesn't discolor in the first place.
Why does sodium electroltyic cell with bicarbonate clean it up? It removes and dissolves the metal salts that give it a black or green color. Bicarb is an electrolyte - it allows electrons to move through the solution. Acid or alkaline work for that. But you want an alkaline - acid caused the problem in the first place.
2006-09-03 18:46:38 · answer #1 · answered by David in Kenai 6 · 0⤊ 0⤋