(a) What is meant by: (i) Colligative properties (ii)Molality of a solution
(b) What concentration of nitrogen should be present in a glass of water at room temperature? Assume a temperature of `25^(@)C`, a total pressure of `1` atmosphere and mole fraction of nitrogen in air of `0.678`. [`K_(H)` for nitrogen `=8.42xx10^(-7) M//mm Hg`]

Explanation

### Step-by-Step Solution:

#### (a) Definitions:
1. **Colligative Properties**:
- Colligative properties are properties of solutions that depend on the number of solute particles in a given amount of solvent, regardless of the nature of the solute. Examples include boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure.

2. **Molality of a Solution**:
- Molality (m) is defined as the number of moles of solute per kilogram of solvent. It is expressed mathematically as:
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