A solution of NaNO₃ that contains 120 grams of solute dissolved in 100 grams of H₂O at 50 Celsius is best described as?
A. Unsaturated
B. Saturated
C. Supersaturated
D. Concentrated
The Correct Answer and Explanation is :
To determine whether the solution of sodium nitrate (NaNO₃) in water is unsaturated, saturated, supersaturated, or concentrated, we must first understand some key concepts about solutions.
Definitions
- Unsaturated Solution: This is a solution that contains less solute than can be dissolved at a given temperature. More solute can be added without exceeding the solubility limit.
- Saturated Solution: A solution that has dissolved the maximum amount of solute at a given temperature. At this point, any additional solute will not dissolve and will remain as a solid.
- Supersaturated Solution: This occurs when a solution contains more solute than can typically be dissolved at a specific temperature. This is usually achieved by heating the solvent to dissolve more solute and then carefully cooling it.
- Concentrated Solution: This term generally refers to a solution that has a relatively large amount of solute compared to the amount of solvent. The exact definition can vary based on context.
Analysis of the Given Problem
At 50 °C, the solubility of NaNO₃ in water is approximately 90 grams per 100 grams of water. In this case, the solution contains 120 grams of NaNO₃ dissolved in 100 grams of water.
- Comparison to Solubility: Since 120 grams of NaNO₃ exceeds the solubility limit of 90 grams at 50 °C, the solution cannot be classified as unsaturated or saturated.
- Supersaturation: The solution has more solute than the maximum solubility, indicating that it is supersaturated.
- Concentration: Although this solution may also be considered concentrated due to the large amount of solute relative to the solvent, the critical point here is that it exceeds the solubility limit.
Conclusion
Based on the analysis, the correct answer to the question is C. Supersaturated. The solution contains more solute than can be dissolved at the given temperature, leading to a supersaturated state.