Give reason for the following observations. (a) Naphthalene balls disappear with time without leaving any solid.
Naphthalene balls are white solid balls. Solids have definite shapes and volumes and also their particles are arranged in a highly ordered fashion. So, naphthalene balls are very rigid. Solids can be changed into liquids via fusion and liquids can be changed into gases via vaporisation. But solids can also be changed directly into gaseous state without having to undergo the liquid state in between. This process is called sublimation.Naphthalene sublimes easily at room temperature. Unlike ice (solid state of water), which at first converts into the liquid state, and then finally into the vapour state, naphthalene directly undergoes phase transition from the solid phase to the vapour phase. It does not go through the intermediate liquid phase. Hence, naphthalene balls start to disappear gradually with time without leaving any solid. Naphthalene balls are white solid balls. Solids have definite shapes and volumes and also their particles are arranged in a highly ordered fashion. So, naphthalene balls are very rigid. Solids can be changed into liquids via fusion and liquids can be changed into gases via vaporisation. But solids can also be changed directly into gaseous state without having to undergo the liquid state in between. This process is called sublimation. Naphthalene sublimes easily at room temperature. Unlike ice (solid state of water), which at first converts into the liquid state, and then finally into the vapour state, naphthalene directly undergoes phase transition from the solid phase to the vapour phase. It does not go through the intermediate liquid phase. Hence, naphthalene balls start to disappear gradually with time without leaving any solid.
