1.Consider the following solvent pairs when mixed: which are immiscible/miscible? If the solvents are immiscible, which solvent would be in the top layer?
a.hexane and water
immiscible- hexane on top bc less dense
b.methylene chloride and water
immiscible – water on top bc less dense
c.ethanol and water
d.ether and waterslightly
miscible, ether on top
Solvent with the lower density will be on the top layer
2. Phenols don’t exhibit the same pKa values as other alcohols; they are generally more acidic. Using the knowledge that hydrogen acidity is directly related to the stability of the anion formed (the conjugate base), explain why phenol is much more acidic than cyclohexanol.
Acidity is a measure of ionization. An acid will dissociate to proton (H+) and the conjugate base (or anion). The more stable the anion is, the stronger the acid. In your example, phenol dissociates to phenoxide anion. This anion is resonance stabilized -ie- the negative charge is spread out from the oxygen to 3 of the ring carbons. In cyclohexanol anion, the charge is not resonance stabilized and the minus charge is firmly placed on the one oxygen atom.3. The pKa of 2,4-dinitrophenol is 3.96. Could you separate it from benzoic acid using the extraction procedures in this experiment?
1.Sodium bicarbonate (WB):deprotonate Carboxylic acid (COOH)
2.HCl:Acid neutralize, deprotonate COO-
3.Brine:dehydrates (remove dissolved water)
4.Mg2SO4(s) Anhydrous magnesium sulfate: remove dissolved water, add solid until it no longer clumps together
1) Compare results to other teams in your lab. Do you all agree on the composition of themixture? If your group disagrees, how could you figure out who is right?
2) Did you recover all of the dissolved solids?
3) Write chemical equations for the acid-base reactions that occur during extraction and neutralization of these compounds
4)What is the difference between “extracting” and “washing”Extraction is the process of removing a compound you want from a mixture using a solvent. The solvent and mixture must be immiscible. Washing is different in that you are removing unwanted from a mixture using a solvent. CHAPTER 6:Notes:?Steam distillation – oils isolated from their plant sources. Have high BP so use suspended in water. Water vaporizes its extracts the essential oils and carries them overinto the collection flask. Separate water.
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