Nail VS Soy-Sauce
Can soy sauce dissolve a nail?
Perform this experiment only under adult supervision.
- 2 nails;
- wax candle;
- 2 crocodile clip wires;
- battery holder with 4 AAA batteries;
- soy sauce.
Apply some melted candle wax to the first nail. Use a knife to make a 2 mm gap in the wax coating. Put two nails in a glass and immerse them in soy sauce. Connect to a battery holder with 4 AAA batteries. Connect the red crocodile clip (positive) to the wax-coated nail, and the black crocodile clip (negative) to the bare nail. Leave for 30-40 minutes. Remove the wax-coated nail from the sauce and wipe it with a paper towel. The nail has dissolved at the gap in the wax! You can break it easily using just your hands.
Soy sauce contains a considerable amount of salts, mainly sodium chloride. Thus, it is able to conduct an electric current. When the nails in the solution are connected to a battery, the electric circuit closes. On the positive electrode - the waxed nail, the unprotected metal dissolves:
Fe⁰ - 2e = Fe²⁺
Fe⁰ - 3e = Fe³⁺
Аnd on the negative electrode, gaseous hydrogen is released:
2H₂O + 2e = H₂↑ + 2OH-
But another chemical process will take place in the solution itself: the resulting reaction products will react with each other and precipitate in the form of iron(II) and iron(III) compounds. A similar experiment is included in the “Corrosion” kit from the MEL Chemistry subscription.