1. The glassware that is to be used for a Grignard reaction iswashed with water and acetone, and dried thoroughly before thereaction is to be performed. Select the most likely reason why.
  a. Acetone is needed to react with the silanolgroups on the surface of the glassware.
  b. The acetone adheres to the sides of theglassware as it dries, and it catalyzes the formation of theGrignard reagent.
c. Grignard reactions are highly endothermic, and residual waterwill freeze during the reaction.
d. If the glassware is not completely dry, residual water oracetone will react with the Grignard reagent.
2. A Grignard reaction is to be performed in diethyl ethersolvent. Select the appropriate grade of diethyl ether for aGrignard reaction.
a. anhydrous grade
b. spectroscopy grade
c. ACS grade
d. technial grade
3. Crude triphenylmethanol was recrystallized using a 2:1mixture of hexane:ethanol. Select the most likely reason why thisrecrystallization solution was chosen over pure ethanol.
a. Formation of triphenylmethanol crystals in the presence ofpure ethanol is rapid, resulting in lower purity.
b. Triphenylmethanol is very soluble in pure ethanol and itsrecovery during recrystallization would be low.
c. Hexane stabilizes the phenyl groups of triphenylmethanol,protecting it from decomposition in the presence of heat.
d. Triphenylmethanol is relatively insoluble in pure ethanol,and not enough of it would dissolve for a recrystallization.
4. Which of the following is NOT a reason why heating a reactionmixture directly on the surface of a hot plate can beproblematic?
a. Hot plates can heat glassware unevenly, which can lead tostress and cracking.
b. It is difficult to measure and maintain the temperature of areaction when using the common, traditional style of hot plate.
c. Flammable solvents with low boiling points may ignite.
d. Hot plates cannot heat above 200 °C.
5. A Grignard reaction is performed by heating phenylmagnesiumbromide and benzophenone under reflux in diethyl ether. Given thatdiethyl ether boils at 35 °C and benzophenone boils at 305 °C,select the appropriate temperature for the reflux.
a. 35 C
b. 25 C
c. 305 C
d. 100 C
