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Recrystallization

Q. 1 Why is the impure solid dissolved in the minimum quantity of hot solvent? If excess solvent is used, (a) some of the insoluble impurities shall remain in the filtrate in step 4. (b) the yield would drop as more solute will remain in the mother liquor in step 6.

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Recrystallization

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  1. Q. 1 Why is the impure solid dissolved in the minimum quantity of hot solvent? If excess solvent is used, (a) some of the insoluble impurities shall remain in the filtrate in step 4. (b) the yield would drop as more solute will remain in the mother liquor in step 6. Recrystallization

  2. Q.2 Why is hot filtration done in ways as described by step 3 ? (a) Hot filtration is to minimize crystallization of filtrate before leaving the funnel. (b) A short-stem funnel fitted with a piece of fluted filter paper is to speed up the filtration so as to minimize crystallization of filtrate before leaving the funnel.

  3. Q.3 Why are the crystals washed in ways as described by step 6 ? (a) Washing the crystals with the mother liquor (a saturated solution) can dissolve no more crystals.  the yield is not reduced. (b) Washing the crystals with cold solvent can remove the mother liquor (with impurities dissolved) from the crystals.

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