Question

2. A solution containing a mixture of naphthalene, benzoic acid, and benzaldehyde is analyzed via TLC and GC. Use the structures and properties of the compounds to aid in answering the following questions. A. In the TLC experiment, the mixture is spotted on a silica TLC plate and eluted with a 1:1 mixture of hexanes and ethyl acetate. Three spots are observed on the plate, with Re values of 0.25, 0.58, and 0.74. Indicate which spot corresponds to which compound. 3 points R: = 0.25 B. Give a rationale for your selections in 2A. 2 points Rr 0.58 R: = 0.74 C. Indicate what would happen to the Ri value of each compound (increase or decrease) if the elution solvent in the TLC experiment was changed to pure hexanes 3 points Naphthalene R value will (select one): Benzoic Acid Rvalue will (select one): Benzaldehyde Rvalue will (select one): D. In the GC analysis of this mixture, the three peaks on the chromatograph have retention times of 4.55, 5.32, 3 points Peak 1 4.55 min 2 points Peak 2 5.32 min Peak 3 7.15 min

Answer 1