Acetophenone reacts with diethyl carbonate in the presence of sodium ethoxide followed b

acidification gives
	1.	-keto ester
	2.	1,3-diketone
	3.	-keto aldehyde
	4.	1,3-dialdehyde

y

ethoxide ion serves as a base and abstract H⁺ from acetophenone forming

Ph-CO-CH₂^- , now this will attack on C₂H₅O-CO-OC₂H₅   to give Ph-CO-CH₂-CO-OC₂H₅ (Beta keto ester)

rxn is similiar to aldol condensation ..

but if acetophenone and ethoxide ions are in excess then product will be

 Ph-CO-CH₂-CO-CH₂-CO-Ph