Introduction:
In this question, we are asked to determine which aqueous solution will have the maximum vapor pressure at a constant temperature. The options given are 1 molal NaCl (aq), 1 molar NaCl (aq), 1 molal H2SO4 (aq), and 1 molar H2SO4 (aq). To answer this question, we need to understand the concept of colligative properties and how they affect vapor pressure.

Colligative Properties:
Colligative properties are properties of a solution that depend on the number of solute particles present, rather than the nature of the solute itself. Vapor pressure is one such colligative property. It is the pressure exerted by the vapor of a liquid in equilibrium with its pure liquid phase at a given temperature.

Vapor Pressure and Concentration:
According to Raoult's law, the vapor pressure of a solution is directly proportional to the mole fraction of the solvent in the solution. The mole fraction is the ratio of the number of moles of the solvent to the total number of moles in the solution.

Comparing the Solutions:
Let's compare the given solutions and determine which one will have the maximum vapor pressure:

1. 1 molal NaCl (aq):
- This solution has a molality of 1 molal, which means it contains 1 mole of NaCl dissolved in 1 kilogram of water.
- Since NaCl is an ionic compound, it dissociates into Na+ and Cl- ions in water.
- The total number of solute particles in this solution is 1 mole of Na+ ions and 1 mole of Cl- ions.
- The mole fraction of the solvent (water) in this solution is 1/(1 + 1 + 1) = 1/3.

2. 1 molar NaCl (aq):
- This solution has a concentration of 1 molar, which means it contains 1 mole of NaCl dissolved in 1 liter of water.
- Similar to the previous solution, NaCl dissociates into Na+ and Cl- ions in water.
- The total number of solute particles in this solution is 1 mole of Na+ ions and 1 mole of Cl- ions.
- The mole fraction of the solvent (water) in this solution is 1/(1 + 1 + 1) = 1/3, which is the same as the previous solution.

3. 1 molal H2SO4 (aq):
- This solution has a molality of 1 molal, which means it contains 1 mole of H2SO4 dissolved in 1 kilogram of water.
- H2SO4 is a strong acid and dissociates completely in water to form 2 H+ ions and 1 SO4^2- ion.
- The total number of solute particles in this solution is 2 moles of H+ ions and 1 mole of SO4^2- ions.
- The mole fraction of the solvent (water) in this solution is 1/(1 + 2 + 1) = 1/4.

4. 1 molar H2SO4 (aq):
- This solution has a concentration of 1

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