As you know ethanol is a an alcohol and alcohol is a hydrocarbon. Alcohol is made up of a carbon chain which Is always non polar and a OH group which is polar. According to the solubility rule like substances dissolves like substance. Using ethanol chemical formula. Ethanol has a 2 carbon chain and a OH group. water is polar so it will be attracted to the OH group. Carbon chain on the other hand is nonpolar so it will be repelled from the water.
Therefore the Solubility of alcohols is determined by the stronger of the two forces. The strength of the attraction of the OH group, and the amount of water they dissolve in.