The diagram illustrates the structure of a compound named ethanoic anhydride. $1\ \text{mol}$ of ethanoic anhydride reacts with water to produce only $2\ \text{mol}$ of a carboxylic acid. This carboxylic acid then reacts with ethanol to produce an ester. What number of moles of water react with $1\ \text{mol}$ of the ethanoic anhydride, and what is the ester structure?