[gimlipig]

Can anyone help me figure out the difference between these two molecules on IR spectrums?

I need to be able to justify how this spectrum represents the compound that it represents:



And not this molecule:




I know that the IR shows the presence of an arryl group with a carbonyl group, but how can I tell which ketone it is?

[dexangeles]

what have you done so far?
have you marked the sp2, sp3 stretches, etc...?
it would be easier if you could compare that IR with the othe molecules IR