Which of the following is most likely missing from a solubility graph to make it complete and useful for interpreting solubility rules?

• A. The pH values of the solutions
• B. The atomic numbers of the elements involved
• C. The chemical formulas of insoluble compounds
• D. The temperature axis

Answer: (D)

Verified step by step guidance

1. Understand that a solubility graph typically shows how the solubility of a substance changes with temperature, so the temperature axis is essential for interpreting the data.
2. Recognize that pH values, atomic numbers, or chemical formulas might provide additional information but are not fundamental axes for a solubility graph.
3. Identify that the missing element making the graph incomplete is the temperature axis, which allows you to see how solubility varies as temperature changes.
4. Recall that solubility is often expressed as grams of solute per 100 grams of solvent plotted against temperature, so without the temperature axis, the graph cannot show this relationship.
5. Conclude that including the temperature axis completes the graph and makes it useful for applying solubility rules and predicting solubility behavior under different conditions.