[SwedishChef]

Hopefully someone can clarify something for me regarding a specific synthesis reaction.
The product synthesized is 5-benzylbarbituric acid, which is a biologically inactive compound of its respective family.

1. 0.46 g of sodium metal added to 50 mL abs. ethanol and heated /w a hot pad until all traces of Na(s) dissolve.
2. To the sodium ethoxide soltn., 5.00 g of dry benzylmalonate was added, immediately followed by the addition of a hot soltn. consisting of 1.2 g of dry urea having been dissolved in 22 mL of abs. ethanol.
3. The resulting mixture was refluxed for 2 hours in a reflux apparatus /w a calcium chloride drying column.
4. After completion of the reaction, the solution was acidified with 20.0 mL of 3 M HCl, and then the volume of the solution was reduced to approximately 1/2 by removal of the ethanol, which was accomplished by using a rotary evaporator.

Obviously, there are a couple other proceeding steps(i.e. crystallization, collection, rinse, recrystallization, etc.). However, I'm curious to know the purpose of acidifying the solution with the 3 M HCl. Could someone please explain this? Thank you!