Question

water can also form hydrogen bonds with other types of molecules. in your body right now, for example, there are trillions and trillions of hydrogen bonds between water and dna and proteins and other molecules. but heres another key factoid: not all molecules can form hydrogen bonds with water. lets try a challenge question. the diagram below contains two different molecules, labeled a and b. which molecule(s) can form hydrogen bonds with water? ○ both molecules. they both contain hydrogen atoms. ○ only molecule a. some of its atoms have partial charges, which are attracted to the partial charges in water. ○ only molecule b. some of its atoms have partial charges, which are attracted to the partial charges in water. ○ neither molecule. all the electrons in each atoms outer shell are paired, so they cannot form any more bonds. nice work. being able to predict which molecules, or which region of a molecule, can interact with water is a critical skill for success in biology. that also brings us to two new vocabulary terms. a hydrophilic molecule is one that can interact readily with the partial charges on water. if a molecule contains mostly nonpolar covalent bonds, it is considered hydrophobic because it cannot interact readily with the partial charges on water. did you fully understand the concept covered in this section?

Explanation:

Hydrogen bonds form between molecules with partial charges. Molecule A (methane) is non - polar (C - H bonds have similar electronegativities, no significant partial charges). Molecule B has oxygen atoms (more electronegative than C and H). In Molecule B, the O - H and C = O bonds create partial charges (O is partially negative, H is partially positive in O - H). These partial charges can interact with the partial charges in water (O in water is partially negative, H in water is partially positive).

Answer:

Only Molecule B. Some of its atoms have partial charges, which are attracted to the partial charges in water.