CHEM experiment (2)

CORROSION OF ION

Corrosion is the term generally used to describe the oxidation of a metal during its interaction with the environment. In this Minilab, you will study the corrosion of a nail and determine the factors that affect this process.

Procedure:
1. Dissolve a package of clear, unflavored gelatin in about 200mL of warm water, Stir in 2mL of phenolphthalein solution and 2mL of potassium hexacyanoferatte(III) solution. Pour the prepared solution into a wide mouth glass jar or Petri dish to a depth of about 1cm.
2. In the liquid gelatin, place a plain iron nail, an aluminum nail, a galvanized iron nail, and a painted iron nail of the type used for paneling. Space the nails far apart.
3. Label the jars or Petri dish with your name, and leave it for several hours /overnight. Handle the jar of dish carefully until the gelatin has set.
4. Record your observations regarding an interaction of the nails with the substance on the gelatin.

Analysis
1. Which of the nails have reached with the substance in the gelatin?
2. If any of the nails have not corroded in the solution can you suggest a reason why they haven’t ? What methods are commonly used to prevent of minimize corrosion?
3. Any blue color in the gelatin is due to the formation of iron (II) ions and their interaction with the hexacyanoferatte(III) ion. Any pink or red color in the gelatin is due to the gaining of electrons by the oxygen and water molecules, forming basic hydroxide ions that turn the phenolphthalein pink. Which of these reactions is oxidation and where does is occur on the reacting nail?