What is the phenomenon called when a naphthalene ball is heated and it directly gets converted into gas?

The phenomenon is called sublimation. Sublimation is a process by which a solid substance is converted directly into a gas, without passing through the liquid state. This occurs when the substance is heated and the pressure is low enough that the gas can form without the need for a liquid intermediate.

Naphthalene is a white crystalline solid that is commonly used in mothballs and other insect repellents. When a naphthalene ball is heated, it undergoes sublimation and converts directly into a gas, which is why the odor of the mothballs can be detected. Camphor is another example of a substance that undergoes sublimation when heated.

Sublimation is a unique phenomenon that is different from other processes such as dissolution, decomposition, and dissociation. Dissolution involves the process of a solid dissolving into a liquid to form a solution. Decomposition involves the breakdown of a substance into simpler substances through chemical reactions. Dissociation involves the separation of a compound into its individual ions in a solution.

In summary, the process of a naphthalene ball getting converted directly into a gas upon heating is known as sublimation.