1. Based on your knowledge of the mechanism involved in the nitration of methyl benzoate, what role(s) would you expect sulfuric acid to play in the nitration of benzaldehyde?

2. During the purification of acetyl ferrocene by column chromatography, hexanes are used to elute the unreacted ferrocene first. Upon subsubsequent elution with (1:1) hexane/Ch2Cl2 the acetyl ferrocene starts to move down the column. Explain the theoretical principle underlying this purification method.