1. Explain the extraction procedures by using separatory funnel is used to separate a substance

Answer:

a. Support the separatory funnel in a ring on a ringstand. Make sure stopcock is closed

b. Pour in liquid to be extracted

c. Add extraction solvent

d. Add ground glass stopper ( well grassed)

e. Pick up separatory funnel with the stopper in place and stopcock closed, and rock it once gently

f. Then, point the stem up and slowly open the stopcock to release excess pressure. Close the stopcock. Repeat the procedures until only a small amount of pressure is released when it is vented

g. Shake the separatory funnel vigorously

h. Vent frequently to prevent pressure buildup, which can cause the stopcock and perhaps hazardous chemicals from blowing out.

i. Let the funnel rest undisturbed until the layers are clearly separated

j. While waiting, Remove the stopper and place a beaker flask under the sep funnel

k. Carefully open the stopcock and allow the two layer to drain into the flask.

2. Explain the technique to be done if you want to separate a mixture of benzoic acid and p- methoxyphenol when they are dissolved in dichloromethane

Answer:

a. Don’t use NaOH because it will react with benzoic acid.

b. Use of weak acid like NaHCO₃ will differentative between the compounds

c. Strong organic acids would be deprotonated and ionized, while weak organic acids such as phenols would not be deprotonated

3. Ten grams of compounds (x) is dissolved in 90 mL of water. The distribution coefficient for compound (x) between hexanes and water is 5 (K=5). How much of compound (X) will be in the hexanes if you extract it from the water with three sequential extractions using 30 mL of hexanes each time, and then combine the hexanes extracts?

Answer:

Known: mass of compounds ( x ) = 10 g

Volume of water= 90 mL

K compound ( x ) = 5

Asked: amount of compound (X)….?

Solution: 90 mL = 3 times 30 mL

q =

q =

q = 0.047 %

amount of compound x that have extracted

m =

m= 0. 47 gram

4. Consider the following solvent pairs. If mixed together, which pairs would form two layers? If they from two layers, which solvent would be on top?

a. Hexanes and water

b. Water and methylene chloride

c. Hexanes and methylene chloride

d. Methanol and hexanes

e. Ethanol and water

f. Acetone and toluene

Answer

a. Hexanes and water will forms two layers because hexanes is organic solvent and soluble in water and water would be on the top layer.

b. Water and methylene chloride will forms layers because methylene chloride is organic solvent and soluble in water and water would be on the layer.

c. Hexanes and metheylene chloride will not forms two layers because both of them are organic solvents

d. Methanol and hexanes will not forms two layers because both of them are organic solvents

e. Ethanol and water will forms two layers because Ethanol is organic solvent and soluble in water and water would be on the top layer.

f. Acetone and toluene will not forms two layer.