To solve this problem, we need to understand the definition of a one molal solution.$\\$A one molal solution means that there is 1 mole of solute dissolved in 1 kg (1000 g) of solvent.$\\$Given in the problem:$\\$• The solution contains 0.5 mole of solute.$\\$Since the solution is one molal, we can set up a proportion to find the mass of the solvent:$\\ \frac{0.5 \ mole \ of \ solute}{x \ g \ of \ solvent} = \frac{1 \ mole \ of \ solute}{1000 \ g \ of \ solvent} \\$Cross-multiply to solve for $x: \\ 0.5 \times 1000 = 1 \times x \\ 500 = x \\$Therefore, there are 500 g of solvent in the solution.$\\$This corresponds to Option 2.