Normal Phase TLC using ethyl acetate as eluent Compounds 1-3 were analyzed by normal phase TLC (shown) using ethyl acetate as the eluent. Assign spots on the TLC plate to compounds 1-3.
  1: 2-acetoxybenzoic acid 2: 2-hydroxybenzoic acid 3: benzoic acid
  
  


I asked a question about TLC and I received some mixed answers, so I'd like to see if my understanding of TLC is fine.

We're using normal phase TLC so lower Rf compounds will be more polar. $0.47$ is the most polar compound, $0.70$ is the least polar compound.

Ethyl acetate is polar. Does the eluent polarity just determine where the compounds will run on the TLC?
TLC is only about polarity. 
Since all three compounds share the benzoic acid functionality, we only have to consider the rest. 
Then we have three compounds: $\ce{R-OCOCH3}$, $\ce{R-OH}$ and $\ce{R-H}$.

In general the polarity is:

alkane &lt; ester &lt; alcohol


That is what we have here also: 3 &lt; 1 &lt; 2.

The one with the lowest polarity will have the highest R$_f$. 
To show that it works, I have run them on a silica TLC plate with AcOEt:



AcSA: acetylsalicylic acid; SA: salicylic acid; BA: benzoic acid.