[a confused chiral girl]

I have tried this question, but it does not look right to me somehow. I don't think the OH will get reduced to H on the end, but I don't know how else I can predict it. thanks!!

[Alberto_Kravina]

It is impossible to reduce OH to H just so simply. you could dehydrate the CH₂-CH₂-OH group to CH=CH₂ and then hydrogenate the double bond to single bond (i.e. with nascent hydrogen)

[a confused chiral girl]

sorry!! I mean...the product that is drawn is just my guess. I am looking for the product when heat is added to that reactant. So, totally ignore that product drawn as it is just my "guess'.

[Albert]

Ever heard of decarboxylation?

[taurean]

Ph-CO-CH3 is the answer.  Beta-keto carboxylic acids undergo decarboxylation (-CO2) when heat is added, to give the corresponding ketone as a product.

[Albert]

Ok, now that taurean has told you the answer, check out the mechanism. I hope it'll help you to understand (and appreciate) this wonderful reaction. 

[a confused chiral girl]

thank you so much. I studied the mechanism (did you draw it by the way? or did you find it on the internet?  ) and I understand how the electron movements will give those products. But just by looking at the reactant there, I would have never ever knew this is decarboxylation reactant.
The answer that Taurean said is different from yours though...he said it's Ph-CO-CH3 and the reaction mechanism you posted is CH3-CO-CH3...so which one is correct?

[Albert]

The answer that Taurean said is different from yours though...he said it's Ph-CO-CH3 and the reaction mechanism you posted is CH3-CO-CH3...so which one is correct?

Looking at the picture I drew, paying attention to the fact I wrote R (neither Ph nor any other partucular group), can you see that, while tauteran tells the answer for your specific question, I gave you a general one, to help you deal with this kind of reactions in future?

EDIT: I've modified the picture: it's now better-looking and more useful than before.