Comment on the suitability of running the infrared spectrum under each of the fo
ID: 728683 • Letter: C
Question
Comment on the suitability of running the infrared spectrum under each of the following conditions. If there is a problem with the conditions given, provide a suitable alternative method.a. A neat spectrum of liquid with boiling point of 150 C is determined using salt plates.
b. A neat spectrum of liquid with boiling point of 35 C is determined using salt plates.
c. A KBr pellet is prepared with a compound that melts at 200 C.
d. A KBr pellet is prepared with a compound that melts at 30 C.
e. A solid aliphatic hydrocarbon is determined as a Nujol mull.
f. Silver chloride plates are used to determine the spectrum of aniline
g. Sodium chloride plates are selected to run the spectrum of a compound that contains some water.
Explanation / Answer
Nujol is a mixture of hydrocarbons (mineral oil) so its absorptions will tend to be right on top of those of an aliphatic hydrocarbon sample and will be much stronger. The information of the sample will be hidden.Use carbon tetrachloride as the solvent. It has no C-H's so will not hide the info on the hydrocarbon sample.