Please answer all 5 questions (it could be short answers). 5-1. What is the main barrier to separating liquid mixtures of less than 500 mL by distillation? 5-2. A sample mixture of ethyl benzoate (bp 212 Celsius) and dodecane (bp 216.2 Celsius) is injected on two GC columns. Column A has DC710 silicone oil as the stationary phase, and column B uses polyethylene glycol as the stationary phase. Which substance would be certain to elute first from column A and would the same material be expected to elute first from column B? Which column, A or B, would be expected to give the better separation of these two substances?
Please answer all 5 questions (it could be short answers).
5-1. What is the main barrier to separating liquid mixtures of less than 500 mL by distillation?
5-2. A sample mixture of ethyl benzoate (bp 212 Celsius) and dodecane (bp 216.2 Celsius) is injected on two GC columns. Column A has DC710 silicone oil as the stationary phase, and column B uses polyethylene glycol as the stationary phase. Which substance would be certain to elute first from column A and would the same material be expected to elute first from column B? Which column, A or B, would be expected to give the better separation of these two substances?
5-3. Question 5-2 refers to separating a mixture of two high boiling liquids by gas chromatography. These materials have similar boiling points. List several GC variables and conditions that would make it easier to separate these
substances by gas chromatography
5-4. Capillary GC columns have better resolution than packed columns even though the enormous surface area provided by the packing material is absent in capillary columns. Why?
5-5. Preparative GC requires packed columns. Why is this technique limited to these lower resolution columns?
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