Question

During the process of crystallization, the funnel is usually preheated by passing through it just beforehand a little bit of hot pure solvent. This is done in order to
(i) prevent undue cooling
(ii) bring about the crystallization of most of the solute
(iii) remove traces of impurity adhering to the crystals
(iv) premature crystallization during filtration
A. (i), (ii)
B. (ii), (iii)
C. (i), (iv)
D. (i), (iii)

Answer 1

Correct Answer - C
Since the hot solution is almost saturated, the effect of thoroughly cooling the filtered solution is to bring about the crystallization of most of the solute. When this process is complete, the crystals are filtered off using a Buchner funnel and flask and washed carefully with a little cold solvent to remove traces of impurity adhering to them Finally, the crystals are dried or are subjected to further recrystallization until the desired state of purity is reached.