Which of the following best determines whether a substance will dissolve in water according to solubility rules?

• A. The color of the substance
• B. The temperature at which the substance was synthesized
• C. The presence of specific ions such as Na^+, K^+, or NO_3^- in the compound
• D. The molecular mass of the substance

Answer: (C)

Verified step by step guidance

1. Understand that solubility in water is primarily influenced by the chemical nature of the substance, especially the ions or functional groups it contains.
2. Recall the solubility rules, which state that compounds containing certain ions like Na\^+, K\^+, and NO\_3\^- are generally soluble in water regardless of other factors.
3. Recognize that physical properties such as color or molecular mass do not directly determine solubility in water.
4. Note that the temperature at which a substance was synthesized does not affect its inherent solubility properties according to standard solubility rules.
5. Conclude that the best determinant for whether a substance will dissolve in water is the presence of specific ions known to form soluble compounds, such as Na\^+, K\^+, or NO\_3\^-.