1. A particular solvent, at room temperature, dissolves both the impuritie to be
ID: 1082295 • Letter: 1
Question
1. A particular solvent, at room temperature, dissolves both the impuritie to be purified. Is this a good solvent for recrystallization of the com answer pou 2. Why, during recrystallization, may it be come necessary to cool a mixture in an ice bath 3. 4. prior to filtration of the purified compound? Explain why it is impossible to recover 100% of the compoun a) from a recrystallization. How can the measured For what additional purpose is melting point measurement used b) melting point be used to assess the purity of a solid compound?Explanation / Answer
1.No, if a solvent dissoves both impurities and compound at room temperature that solvent is not useful for the recrystallisation this is because if the given solvent dissolves compound very easily at room temperature to get the crystalized pure compound is so difficult means no proper crystalisation takes place.that is why while selecting the solvent we have to choose the solvent which sparingly dissolves the compound.
2.cooling in ice bath is done during recrystalisation because the cooling enhances the formation of pure crystals.
3.To recover 100% of the compound from recrystalisation is impossible because
a)some loss of compound takes place during transferring compound from one beaker to other
b)little amont of compound will be left behind which we cannot avoid.
c)some of the crystal compound may redissolve in the solvent which decreases the recovery of 100% compound.
4.a)If the compound melts lower range than the true melting point then the purity is more if the temperature range is higher than the true melting temperature then the purity is less.
b)By using melting point we can check notonly the purity of a compound butalso sometimes we can identify the compound if they have given unknown compound for crystalisation.
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