Which action is performed by the slightly charged parts of a water molecule when salt (such as NaCl) dissolves in water?

• A. They surround and separate the Na+ and Cl- ions, stabilizing them in solution.
• B. They react with the salt to produce a gas.
• C. They cause the salt to precipitate out of the solution.
• D. They form covalent bonds with the Na+ and Cl- ions.

Answer: (A)

Verified step by step guidance

1. Understand that water is a polar molecule, meaning it has regions of partial positive and partial negative charge due to the difference in electronegativity between hydrogen and oxygen atoms.
2. Recognize that when an ionic compound like NaCl dissolves in water, it dissociates into its constituent ions: Na+ (sodium ion) and Cl- (chloride ion).
3. Know that the slightly positive parts of water molecules (the hydrogen ends) are attracted to the negatively charged Cl- ions, while the slightly negative parts of water molecules (the oxygen ends) are attracted to the positively charged Na+ ions.
4. This attraction causes water molecules to surround each ion, a process called hydration or solvation, which helps to separate and stabilize the ions in solution.
5. Conclude that this interaction prevents the ions from recombining and keeps them dissolved, rather than reacting chemically, precipitating, or forming covalent bonds.