To design an effective experiment on the effect of temperature on the solubility of sugar in water, one must ensure that variables other than temperature are controlled and kept constant across different groups.
In this scenario, John has three groups with different temperatures and is examining how temperature affects the solubility of sugar in water. The volume of water is one such variable that should be kept constant across all groups to ensure a fair comparison.
Given that Group A uses 100 mL of water at a temperature of [tex]\(25^{\circ} C\)[/tex], to maintain consistency and ensure that the change in solubility is solely due to the change in temperature, Group B and Group C should also use the same volume of water.
Therefore, the best volume of water to use in Group B to maintain consistency in experimental conditions is:
100 mL
So, the correct answer is:
A. 100 mL
