As we will see in Chapter 8, the carbonyl group of aldehydes and ketones reacts with wat...

As we will see in Chapter 8, the carbonyl group of aldehydes and ketones reacts with water to form a compound called a hydrate. The hydration of a carbonyl group is catalyzed by acid. Formaldehyde, for example, reacts as shown below. When dissolved in water, formaldehyde exists almost entirely as its hydrate. This aqueous solution is given the name formalin.

The mechanism for this acid-catalyzed hydration is similar to the mechanism of the acid-catalyzed hydration of an alkene to give an alcohol and occurs by the following three steps.

Step 1: Add a proton.

Step 2: Make a new covalent bond between an electrophile (an electron-seeking species) and a nucleophile (an electron-donating species).

Step 3: Take a proton away.

Write an equation for each step and show by the use of curved arrows how each of these steps occurs. Show all bond-forming steps and bond-breaking steps.