Two metals which do not corrode easily are: 1.Platinum 2.Gold i. Corrosion of some metals is an advantage: Example: Corrosion of aluminium is useful. Corrosion of Aluminium occurs when the metal is exposed to oxygen, according to the following reaction : 4 Al(s) + 3 O2 (g) ? 2 Al2 O3 (s) Thus a protective layer of aluminium oxide is formed on the surface of the metal, which renders the metal passive and prevents its further corrosion. ii. Corrosion of metal is a serious problem.: Corrosion of Iron in the presence of oxygen and air leads to formation of brown solid known as rust. This process is called rusting. 4 Fe + 3 O2+ 2x H2O ? 2 Fe2O3.xH2O Corrosion causes damage to car bodies, bridges, iron railings, ships and all objects made of metals (especially Iron). Rusting of iron causes great economic loses every year.

Introduction:

Corrosion is a natural process that occurs when metals react with their surrounding environment, resulting in the deterioration of their physical properties. However, there are certain metals that exhibit exceptional resistance to corrosion. In this response, we will discuss two such metals - stainless steel and gold.

1. Stainless Steel:
Stainless steel is a versatile alloy composed primarily of iron, chromium, and other elements such as nickel and molybdenum. It is widely used in various industries due to its excellent corrosion resistance properties. The key factors responsible for stainless steel's resistance to corrosion are as follows:

Composition: The presence of chromium in stainless steel forms a passive layer of chromium oxide on the metal's surface. This layer acts as a protective barrier against corrosive agents, preventing further oxidation and corrosion.

Chromium Oxide Layer: The passive layer of chromium oxide is self-repairing, which means that if it gets damaged or disrupted, it can quickly reform when exposed to oxygen. This characteristic enhances stainless steel's ability to resist corrosion even in harsh environments.

Uniform Corrosion: Stainless steel exhibits uniform corrosion, which means that the corrosion occurs evenly across its surface. This prevents the formation of localized corrosion sites, such as pits or crevices, that can lead to rapid deterioration.

Alloying Elements: The addition of alloying elements like nickel and molybdenum further enhances stainless steel's corrosion resistance. Nickel increases the stability of the protective oxide layer, while molybdenum improves its resistance to chloride-induced corrosion.

2. Gold:
Gold is a noble metal known for its exceptional resistance to corrosion. It possesses the following characteristics that contribute to its non-corrosive nature:

Chemical Inertness: Gold is chemically inert, meaning it does not react readily with most substances. It remains unaffected by exposure to air, moisture, or common acids and bases. This inertness is due to the strong bonding between gold atoms, which makes it highly stable.

Passivation: Similar to stainless steel, gold forms a passive oxide layer on its surface when exposed to oxygen. This oxide layer acts as a protective barrier, preventing further oxidation and corrosion. Additionally, gold's passivation layer is exceptionally stable, allowing it to resist corrosion under various conditions.

Lack of Reactivity: Gold's lack of reactivity is primarily attributed to its electronic configuration. It has a full outermost electron shell, making it less likely to participate in chemical reactions. This stability makes gold highly resistant to corrosion.

Conclusion:
Stainless steel and gold are two metals that exhibit exceptional resistance to corrosion. Stainless steel's corrosion resistance is primarily due to the formation of a self-repairing chromium oxide layer, while gold's inertness and passivation properties contribute to its non-corrosive nature. The unique characteristics of these metals make them invaluable in various industries where corrosion resistance is crucial.

Gold and platinum do not corrode.