Which statement best explains why oil and water do not mix?

• A. Oil is nonpolar and water is polar, so their molecules do not interact strongly enough to mix.
• B. Oil molecules form hydrogen bonds with water, causing them to separate.
• C. Oil and water have similar densities, preventing them from mixing.
• D. Oil contains ionic bonds while water contains covalent bonds, making them incompatible.

Answer: (A)

Verified step by step guidance

1. Understand the nature of water molecules: Water is a polar molecule because it has a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom, leading to strong intermolecular attractions called hydrogen bonds.
2. Recognize the nature of oil molecules: Oil molecules are generally nonpolar, meaning they do not have significant partial charges and cannot form hydrogen bonds.
3. Recall the principle 'like dissolves like': Polar substances tend to mix well with other polar substances due to strong intermolecular forces, while nonpolar substances mix well with other nonpolar substances.
4. Analyze the interaction between oil and water: Since oil is nonpolar and water is polar, their molecules do not interact strongly enough to overcome the forces holding each type of molecule together, leading to separation rather than mixing.
5. Conclude that the difference in polarity between oil and water explains why they do not mix, making the statement 'Oil is nonpolar and water is polar, so their molecules do not interact strongly enough to mix' the best explanation.