What will happen if a large quantity of NaCl is added to an aqueous solution?

• A. NaCl will not dissolve and will precipitate immediately.
• B. The pH of the solution will decrease significantly.
• C. The concentration of Na+ and Cl- ions in the solution will increase.
• D. The solution will become non-conductive.

Answer: (C)

Verified step by step guidance

1. Understand that NaCl (sodium chloride) is an ionic compound that dissociates completely in water into its ions: Na\textsuperscript{+} and Cl\textsuperscript{-}.
2. When a large quantity of NaCl is added to an aqueous solution, it dissolves until the solution reaches its saturation point, increasing the concentration of Na\textsuperscript{+} and Cl\textsuperscript{-} ions in the solution.
3. Recognize that NaCl is a neutral salt formed from a strong acid (HCl) and a strong base (NaOH), so it does not affect the pH significantly; therefore, the pH will not decrease significantly.
4. Since the solution contains more free ions (Na\textsuperscript{+} and Cl\textsuperscript{-}), its electrical conductivity increases rather than decreases, so the solution will remain conductive.
5. If the amount of NaCl added exceeds its solubility limit, the excess NaCl will not dissolve and will remain as a solid precipitate, but initially, the main effect is the increase in ion concentration.