Question

What is sublimation? Write the names of everyday substances that sublimate.

Answer 1

Hint : We are aware that matter exists in three phases which are solids, liquids and gases. When the matter in any phase is subjected to high or low temperature, it tends to change its phase. When any solid is heated, it converts into liquid and then into gaseous form. But, there are few solids which tend to change directly from solid to gas.

Complete Step By Step Answer:
By now, you have got an idea about what sublimation is. We know that conversion of solid to liquid is called melting and then liquid to gas is called boiling or evaporation. There is an unusual phenomenon where the solids get directly converted into gaseous form without passing through the liquid phase and this process is called sublimation. There are many substances which sublimate and some of them are those which we use in our day to day activities. We usually see camphor(solid) in our mandirs, where it directly starts turning into gas when it is burned. This is a perfect example of the substance undergoing sublimation. The others include naphthalene balls, moth balls etc. The naphthalene balls are actually placed in our wardrobes to prevent the attack of mites and are also placed in wash areas. After a few days, when you observe your wardrobe, these balls disappear as they undergo sublimation. This phenomenon can also be seen in dry ice which is used in ice cream parlors. So, this is all about sublimation.

Note :
These substances sublime easily because they are made of non-polar molecules which are held together by van der waals forces. These are weak forces and their bonds tend to break easily. The reverse process of sublimation also occurs which is termed as desublimation.