Question

Name: Date CHEM 3401 Prelaboratory Assignment, Elimination Reactions of Alkyl Halides Due at the beginning of the lab period Reading Assignment from Zubrick, 9 ed.: Drying agents, Chapter 10, Extraction and Washing. Chapter 15: Elimination Reactions of Alkyl Halides Experiment, GSU Laboratory Manual 1. The concentrated hydrochloric acid you will use in the first day of the laboratory exercise is not 100 % hydrochloric acid. What else is present in the concentrated hydrochloric acid solution, and what are the relative amounts of each component? This answer may be found via the internet. 2. What piece of glassware is used to wash the alkyl halide product? 3. What drying agent is used to dry the alkyl halide prepared in the laboratory? 4. From the perspective of the organic chemistry laboratory, what is a dry liquid? 5. In the reaction that is performed on day one of this experiment, is the alkyl halide product found in the aqueous layer or the organic layer, and is the layer you identified on the top or the bottom?

Answer 1

1) Commercial concentrated acid is 38% w/w HCI aqueous solution (1 am not sure about your specific used HCl grade and hence using often value of % of HCI). If the density of this solution is 1.18g/mL then mass of 1 L solution = 1.18g/mL * 1000mL = 1180 g The 38% w/w for HCl in 1180g = 0.38*1180 = 448.4 g HCl in 1180g of sol. Molar mass of HCl = 36.5 g/ mol Moles of HCl = 448.4g/36.5g/mol = 12.3 moles Molarity = moles/L = 12.3 mol/1L = 12.3 M Thus in 1 L of conc. HCl there is 448.4 g of HCl and 731.6 g of water. 2) Separating funnel is used for the washing of alkyl halide. 3) Grannular Sodium sulfate or magnesium sulfate must have been used as drying agents in this experiment. 4) Dry liquid is the organic solution dryied over the sodium or magnesium sulfate. 5) Alkyl halide is more soluble in organic solvent then the water. Hence it is found in the organic layer. Often, organic layer are of diethyl ether (DEE) or DCM or Chloroform. If it is DEE then it must be top layer. If you used DCM of chloroform then it must be bottom layer.