Final answer:
The freezing point of plasma is lower than the normal freezing point of water due to the effect of solutes present in plasma. Based on the provided information and understanding of freezing point depression, the closest answer would be option A. -1.86°C.
Step-by-step explanation:
The student's question asks what the freezing point of plasma is, given four options: A. -1.86°C, B. -1.00°C, C. -0.56°C, and D. 0.00°C. To answer this, we need to understand freezing point depression, which is a colligative property that describes how the freezing point of a solvent decreases when a solute is added. The examples provided relate to the freezing point depression of different solutions, showing calculations that subtract the change from the normal freezing point of water, which is usually 0.00°C.
From the provided information, we can infer that the freezing point of plasma would be below the normal freezing point of water due to the presence of solutes like ions and proteins in the plasma. Given the examples that relate freezing point depression directly to additions in a solution, the correct answer would be the lowest temperature listed higher than the decreased value given by the colligative property equation, which is option A. -1.86°C.
This temperature indicates the amount by which the freezing point of water is lowered when solutes are present, such as in the case of plasma or other solutions.