Sample pre-lab quiz for Preparation of Alkyl Halides experiment.

1) Whether a reaction will proceed via an SN1 or an SN2 process depends on:

  1. the structure of the reactants
  2. the structure of the products
  3. the reaction conditions
  4. all of the above
  5. a and c

2) If carbocations formed from the following alcohols, which would be the most stable?

3) During the work-up of the reaction mixture, the organic layer, which is mostly product, is washed (or extracted) with saturated aqueous sodium chloride solution. Which layer will be on top in the separatory funnel?

  1. organic
  2. aqueous

4) All the wastes in this experiment go into the aqueous waste container EXCEPT ONE! Which one goes into the organic waste jar?

  1. the saturated aqueous sodium chloride wash of the organic layer
  2. the saturated aqueous sodium bicarbonate wash of the organic layer
  3. the HCl layer from the original reaction mixture
  4. the used test reaction solutions

5) After the washes with saturated aqueous sodium bicarbonate and sodium chloride, calcium chloride is added to the product solution. What is the purpose of the calcium chloride?

  1. to react with t-butyl alcohol to form t-butyl chloride
  2. to neutralize the HCl
  3. to remove water from the product
  4. to bind the product for easier filtration

6) During the work-up of the reaction mixture, the organic layer, which contains most of the product, is washed (or extracted) with saturated aqueous sodium chloride solution. What is the purpose of this wash?

  1. to neutralize any residual HCl in the organic layer
  2. to pull water from the organic layer, thereby "drying" it
  3. to remove colored impurities from the organic product
  4. to increase the concentration of Cl-, thereby encouraging formation of product

7) A student added 2.6 mL of HCl instead of the 26 mL called for in this experiment. Therefore, the student had less moles of HCl than he/she had of t-butyl alcohol. What would be the limiting reagent?

  1. t-butyl alcohol, because HCl is only needed in catalytic amounts
  2. the HCl

Answers.