You can't determine the molarity of the solution with just the information that equal moles of water (H₂O) and sodium chloride (NaCl) are present. Here's why:

* Molarity is moles of solute per liter of solution.

* Water is both the solvent and a component of the solution. You need to know the total volume of the solution to calculate the molarity.

Here's what you need to do:

1. Determine the total volume of the solution: You'll need to know the volume of the water plus the volume of the dissolved NaCl.

2. Calculate the molarity:

* Divide the number of moles of NaCl (the solute) by the total volume of the solution in liters.

Example:

Let's say you have 1 mole of H₂O and 1 mole of NaCl. If the total volume of the solution is 2 liters, then:

* Molarity of NaCl = 1 mole / 2 liters = 0.5 M

Important Note: The volume of the solution will likely be different from the sum of the volumes of the water and NaCl. This is because the dissolution of NaCl in water can cause a change in volume.