Rank the following five compounds in order of decreasing acidity (1 = strongest acid, 5 = weakest acid): p-nitrophenol (O₂N–C₆H₄–OH), phenol (C₆H₅OH), allyl alcohol (CH₂=CHCH₂OH), tert-butyl alcohol ((CH₃)₃COH), and ethanol (CH₃CH₂OH). Provide only the ordered list of compounds.