Chapter 19, Problem 1E

Under which circumstances is it wise to use a mixture of solvents to carry out a crystallization?

What is the effect of weighing a recrystallized organic solid which is not completely dried to the percentage yield? Elaborate.

1. Why is the washing of crystals on the filter paper not as effective a process of purification as crystallization?2. How do you account for the formation of crystals of different sizes in slow and rapid crystallization process?3. What properties should ideally be possessed by a recrystallization solvent?

a student performed a recrystallization on 515 mg of impure compound using ethanol. After isolating the crystals, he obtained only 215 mg of pure product. Knowing that his sample was only slightly impure, he concluded that a significant amount of product was lost. Explain what likely happened and what he can do to recover his product.

What is different about steam distillation

Nitroethylene, HyC = CHNO, is a sensitive compound that must be prepared with great care. Attempted purification of nitroethylene by distillation often results in low recovery of product and a white coating on the inner walls of the distillation apparatus. Explain.

A student recrystallized some impure benzoic acid and isolated it by filtration. He scraped the purified benzoic acid off the filter paper after it had dried and took the melting point as a test for purity. He was surprised that most of the white solid melted sharply between 121 and 122 °C but that a small amount remained unmelted even at temperatures above 200 °C. Explain this behavior.

n-Pentanol is an aliphatic alcohol with many properties similar to ethanol.  Explain why n-pentanol was not considered as a possible recrystallization solvent for fluorene during our laboratory experiment.

In the isolation of eugenol using steam distilation, what will happen if one use instead fractional distillation than steam distillation thank u