$$-\substack{|\\\ce{C}\\|}-\raise0.8em\substack{\ce{O}\\\|\\\ce{C}}-\substack{\ce{H}\\|\\\ce{C}\\|\\\ce{H}}-\substack{\ce{O}\\\|\\\ce{C}\\\\}-\ce{O}-\ce{C2H5}\rightleftharpoons-\substack{|\\\ce{C}\\|}-\substack{\ce{OH}\\|\\\ce{C}\\\\}-\substack{\ce{H}\\|\\\ce{C}\\\\}-\substack{\ce{O}\\\|\\\ce{C}\\\\}-\ce{O}-\ce{C2H5}$$ cetônica enólica