1. The distribution coefficient, K = Cether/Cwater is 10 forcompound Y. What wei

Question

1. The distribution coefficient, K = Cether/Cwater is 10 forcompound Y. What weight of compound Y would be removed from asolution of 4.0 g of Y in 100 mL of water by a single extractionwith 100 mL of ether?

2. Reconsider Question 1 above; what weight of compound would beremoved by two extractions using 50 mL of ether each time?

3. Describe how you would separate a mixture containing benzoicacid and a neutral substance, benzophenone. Both compounds areinsoluble in water and soluble in ether.

4. Assume that during an extraction experiment you have lost trackof which layer is the aqueous layer. How could you determine whichlayer is which by the use of a simple test?

5. The compounds isolated during this experiment may be impure orwet. What effect will this have on the melting points?

6. Most phenols (ArOH) do not react with sodium bicarbonatesolution but do react with sodium hydroxide solution. Describe howto separate, by extraction, a mixture of a water-insoluble phenol(ArOH) and a water-insoluble carboxylic acid (RCOOH).

Explanation / Answer

1/ Let x is the amount of Y in ether (the weight of Y would be removed from the solution), so (4-x) is the amount of Y in water.

KD = c ether/ c water = (x / 100mL) / ((4-x)/100mL) = 10

So there is 3.64g of Y is removed from the solution.

2/

Let x is the amount of Y in ether (the weight of Y would be removed from the solution), so (4-x) is the amount of Y in water.

KD = c ether/ c water = (x / 50mL) / ((4-x)/100mL) = (2x / 100mL) / / ((4-x)/100mL) = 10

2x/(4-x) = 10 then x = 3.33g

So there is 3.33g of Y is removed from the solution.

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