Gases dissolved in molten metals are liberated when cooled giving rise to:
**Core Concept**
Gases dissolved in molten metals are a common phenomenon, particularly in aluminum and magnesium. This occurs due to the solubility of gases like hydrogen, nitrogen, and oxygen in the molten metal, which increases with temperature.
**Why the Correct Answer is Right**
When molten metals are cooled, the solubility of gases decreases, causing them to precipitate out of the solution. This is a result of the decrease in temperature, which reduces the kinetic energy of the metal atoms and decreases their ability to hold dissolved gases. The gases that are liberated include hydrogen, nitrogen, and oxygen, which can lead to porosity and defects in the final metal product.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the context of gases dissolved in molten metals.
* **Option B:** This is not a correct term related to the phenomenon of gases being liberated from molten metals.
* **Option C:** This option is not a correct description of the phenomenon being described.
**Clinical Pearl / High-Yield Fact**
It's worth noting that the liberation of gases from molten metals can be a major issue in the production of certain metals, particularly aluminum and magnesium. This can lead to defects and porosity in the final product, which can have significant consequences for its strength and durability.
**Correct Answer: C. Porosity.**