A student had prepared three ethyl-substituted benzaldehydes, but had neglected to label them. The premed student at

Question:

A student had prepared three ethyl-substituted benzaldehydes, but had neglected to label them. The premed student at the next bench said that they could be identified by brominating a sample of each and determining how many bromo-substituted products were formed. Is the premed student's advice sound?