Final answer:
DNA's solubility in water is due to its polar charged phosphate groups and sugar backbone, which interact with water molecules. These same groups are not as soluble in alcohol, which is less polar. Option (c) reflects the correct explanation for DNA's solubility properties. Correct option is c)
Step-by-step explanation:
DNA Solubility and Chemical Structure:
The physical properties of DNA reflect its chemical structure. DNA's solubility in water is due to the charged phosphate groups and sugars that form the backbone of the DNA molecule. These components are polar and therefore attract other polar molecules such as water. Each phosphate group carries a negative charge which can form electrostatic interactions with water's partial positive charges. Consequently, this interaction makes DNA soluble in water. On the other hand, the nitrogenous bases (adenine, thymine, cytosine, and guanine), while essential for DNA's function, are stacked inside and do not interact directly with water, but instead, form hydrogen bonds with complementary bases on the opposite strand.
Alcohol, however, is less polar than water and has a reduced capacity to interact with the charged phosphate groups. This is why DNA is not soluble in alcohol. Thus, DNA's solubility in water but insolubility in alcohol can be attributed to its chemical structure and the polar nature of its backbone, which allows interactions with water but not with less polar solvents like alcohol.
As for the options provided in the question, the correct explanation for DNA's solubility properties is that the charged phosphate groups and sugars of DNA "like" to interact with polar water molecules, which corresponds to option (c).