I have a doubt in the separation of KNO3 and KClO3 using the method of fractional crystallization First of - Chemistry -

Question

I have a doubt in the separation of KNO3 and KClO3 using the method
of fractional crystallization First of all , when we add this
mixture to water and heat it, making a hot saturated solution and
then cool it ? Why does KCl03 crystallize out ? My second question
is that (after we filterKCl03from the sol Using filtration) why do
we need to heat and then cool the filtrate to obtain KN03 crystals
? Why can't we just evaporate the filtrate , and so water will
evaporate, leaving only KNO3? I also can't understand the whole
concept of crystals and the fact that why do crystals form if we
heat and then cool the mixture

Geetha · Accepted Answer

Dear Suprit Kr Behera

KNO3 and KClO3 can be separated by fractional
crystallisation In this method you have to choose a suitable
solvent so that both the substance to be purified should be soluble
in that solvent but the level of extent is different One is less
soluble and the other is more soluble in that solvent The less
soluble component crystallises out first leaving the high soluble
one Always crystallisation is done from a saturated solution only
Just to make the solution to get completely dissolved we are
heating and on cooling crystals will come out