2021 H2 Chem P1 Q8 — Gases Solution

The answer is D.

Dalton's law (also called Dalton's law of partial pressures) states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases: \(p_\text{total} = p_\text{A} + p_\text{B} + p_\text{C} + \ldots\)

A ✗: This is Avogadro's law, not Dalton's law.

B ✗: The relationship \(p_\text{A} = x_\text{A} \times p_\text{total}\) (partial pressure = mole fraction × total pressure) is true, but it is a result that follows from Dalton's law, not the statement of the law itself.

C ✗: Partial pressure is the mole fraction, not the percentage by mass, multiplied by the total pressure.