The experimentally determined molar mass for what type ofsubstances is always lower than the true value when water is used as solvent. Explain. Give one example of such a substance and one example of a substance which does not show a large variation from the true value.

Explanation

To answer the question, we need to understand the relationship between the dissociation of solutes in a solvent, particularly water, and how it affects the experimentally determined molar mass.

### Step-by-Step Solution:

1. **Understanding Molar Mass**: Molar mass is defined as the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is a fundamental property of a substance.

2. **Colligative Properties**: When a solute is dissolved in a solvent, it affects the physical properties of the solution. These effects are known as colligative properties, which depend on the number of solute particles in the solution rather than the identity of the solute.

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