Final answer:
The statement is false; hydrogen bonds can and do form between water and ammonia molecules due to the polar nature of these molecules, where the slightly positive hydrogen atoms are attracted to the slightly negative oxygen or nitrogen atoms in different molecules.
Step-by-step explanation:
The statement that hydrogen bonds do not exist between water and ammonia molecules is false. Hydrogen bonds are a type of weak interaction that can occur between two polar molecules, such as water (H2O) and ammonia (NH3). Water molecules have a slightly negative charge on their oxygen atom and a slightly positive charge on their hydrogen atoms, while ammonia molecules have a slightly negative charge on their nitrogen atom and slightly positive charges on their hydrogen atoms. This difference in charge allows for hydrogen bonds to form between the hydrogen atom of one molecule and the electronegative atom (oxygen or nitrogen) of another molecule, which is why water and ammonia can indeed form hydrogen bonds with each other.
Hydrogen bonds are crucial for many biological processes, including the stabilization of the structure of proteins and DNA. Although individual hydrogen bonds are weak, their cumulative force can be quite strong, especially in large numbers as found in water. However, it is important to note that hydrogen bonds are not as strong as covalent bonds within molecules.