Which formula represents the vapor pressure of an ideal solution?

The formula for the vapor pressure of an ideal solution reflects how the partial vapor pressures of the components contribute to the total vapor pressure. In this question, the correct choice mathematically describes the relationship between the total vapor pressure and the mole fractions of the components in an ideal solution.

For an ideal solution, Raoult's law states that the partial vapor pressure of each component is proportional to its mole fraction in the liquid phase. The formula correctly indicates that the total vapor pressure (p) can be expressed as the sum of the partial pressures of the components, which depends on their respective mole fractions and their pure component vapor pressures.

In this case, the formulation p = p*_B + (p*_A − p*_B)x_A signifies that the total pressure is derived from the pure vapor pressure of component B, adjusted by the difference in vapor pressures between components A and B when multiplied by the mole fraction of A (x_A). This reflects the change in the overall vapor pressure as the composition of the solution changes—focusing on how the presence of one component alters the vapor pressure due to interactions between the solution’s components.

Other options do not represent the correct relationships as per Raoult's law for ideal solutions. They suggest varying combinations of