Question

2) Give reason for the following observations
a) Napthalene balls disappear with time without leaving any solid.
b) The smell of hot sizzling food reaches you several metres away, but to get the smell from cold
food you have to go close.​

Answer 1

HeRe Is Your Ans ⤵

******

➡A = Naphthalene undergoes sublimation easily i.e., the change of state of naphthalene from solid to gas takes place easily. Thus, naphthalene balls disappear with time without leaving any solid

➡B = Solids diffuse at a very slow rate. But, if the temperature of the solid is increased, then the rate of diffusion of the solid particles into air increases. This is due to an increase in the kinetic energy of solid particles. Hence, the smell of hot sizzling food reaches us even at a distance, but to get the smell from cold food we have to go close

******

Follow Me

Answer 2

a) Because naphthalene balls show sublimation and directly change to gas at room temperature.

b) the fragrance of hot sizzling food diffuses and reaches far away so we can smell it............. thanks