NCERT Questions – 3 (a)

Give reason for the following observations.

(a) Naphthalene balls disappear with time without leaving
any solid.

Answer:

• Sublimation: Naphthalene has a property called sublimation, which means it changes directly from a solid to a gas without becoming a liquid.
• When exposed to air, naphthalene gradually evaporates into the surroundings.
• Since it converts into gas, no solid residue is left behind.
• Other substances that exhibit sublimation include camphor, dry ice (solid CO₂), and iodine.