The correct option is Dalton’s law of partial pressures.
Explanation
The question addresses the fundamental laws governing the pressure exerted by mixtures of gases or vapours. Specifically, it seeks the principle that aggregates individual component pressures into a total system pressure.Detailed Analysis
Dalton’s Law of Partial Pressures states that for a mixture of non-reacting gases (or vapours), the total pressure exerted is equal to the sum of the partial pressures of the individual components. Mathematically, this is expressed as:
\[ P_{total} = p_1 + p_2 + p_3 + \dots \]
This law directly establishes the relationship between the total vapour pressure of a mixture and the partial pressures of its constituents.
Comparison with Other Options:
- Raoult’s Law: Applies to solutions of volatile liquids. It relates the partial vapour pressure of a specific component to its mole fraction in the solution (\( p_i = x_i p_i^0 \)). While it calculates partial pressures, the summation of these to find the total pressure is an application of Dalton’s Law.
- Henry’s Law: Relates the solubility of a gas in a liquid to the partial pressure of that gas above the liquid surface.
- Graham’s Law: Relates the rate of diffusion or effusion of a gas to its density or molar mass.
Key Takeaway:
Dalton’s Law of Partial Pressures is the fundamental principle that defines the total pressure of a gaseous mixture as the arithmetic sum of the partial pressures of its individual components.