Ou are subliming camphor and you note that pure camphor is condensing nicely on the cold finger. You check on the process several minutes later and you see that the amount of camphor on the cold finger has not changed appreciably since the last time you looked at it. However, there is still plenty of impure camphor left at the bottom of the flask. What do you suppose is the reason and what do you need to do.

The reaction is endothermic

Increase temperature of the flask

Explanation:

Sublimation is a phenomenon in which a substance changes directly from solid to gas,without passing through the liquid phase.

Camphor is a sublime substance. The sublimation of camphor is an endothermic reaction. This implies that energy is absorbed in the process.

For an endothermic reaction, the equilibrium position is shifted towards the right hand side by increasing the temperature of the system. Hence, if the flask is heated, more camphor will condense within a shorter time interval.