What order would these compounds elute in a 3:1 hexanes:ethyl acetate TLC run? I would figure the order would be (in order of smallest Rf to largest) W, Z, Y, X. Is the carboxylic acid more polar than the acetic anhydride?
Making predictions about elution order is always guesswork but based on my experience I would expect acetic acid to streak off the baseline, The benzyl alcohol to be of low Rf but above the acetic acid, the benzyl acetate Y to run high and I really don't know about the acetic anhydride, I suspect it will hydrolyse on the plate to give you more acetic acid so you will not see a separate spot. How are you planning on visualising these?