No. Of moles of solute =1No. Of moles of h20 = 1000/18= 55.556Mole fraction= 1/1+55.556=0.0177

Definition of Molality
Molality is defined as the number of moles of solute dissolved in 1 kg of solvent. It is denoted by 'm' and its unit is mol/kg.

Formula to Calculate Molality
Molality can be calculated using the following formula:

Molality (m) = Number of moles of solute / Mass of solvent in kg

Mole Fraction of Solute in 1 Molal Aqueous Solution
Mole fraction is defined as the ratio of the number of moles of a component to the total number of moles in the solution. In a 1 molal aqueous solution, 1 mole of solute is dissolved in 1 kg of solvent (water).

Let's assume that the solute is represented by 'A' and the solvent is represented by 'B'.

The number of moles of A in the solution will be equal to the number of moles of solute added to the solution.

The number of moles of B in the solution will be equal to the mass of water in the solution divided by its molar mass (18 g/mol).

Therefore, the mole fraction of A in the solution can be calculated using the following formula:

Mole fraction of A = Number of moles of A / (Number of moles of A + Number of moles of B)

In a 1 molal aqueous solution, the number of moles of A will be equal to 1 mole (as 1 mole of solute is dissolved in 1 kg of solvent).

The mass of water in the solution will be equal to 1000 g (as 1 kg of water is used to dissolve the solute).

Therefore, the number of moles of B in the solution will be equal to 1000 g / 18 g/mol = 55.56 mol.

The mole fraction of A in the solution can be calculated as follows:

Mole fraction of A = 1 mole / (1 mole + 55.56 moles) = 0.0179

Therefore, the mole fraction of solute (A) in a 1 molal aqueous solution is 0.0179.