The problem asks for the molarity of a urea solution. Molarity (M) is defined as the number of moles of solute dissolved per liter of solution.

$M = \frac{\text{moles of solute}}{\text{Volume of solution (in L)}}$

We are given the following information:

• Mass of urea (solute) = 120 g
• Molar mass of urea (CH₄N₂O) = 60 g/mol
• Mass of water (solvent) = 1000 g
• Density of the solution = 1.15 g/mL

Let's calculate the required values step-by-step.

Step 1: Calculate the number of moles of the solute (urea). The number of moles is calculated by dividing the given mass by the molar mass. $\text{Moles of urea} = \frac{\text{Mass of urea}}{\text{Molar mass of urea}} = \frac{120 \text{ g}}{60 \text{ g/mol}} = 2 \text{ mol}$

Step 2: Calculate the total mass of the solution. The total mass of the solution is the sum of the mass of the solute and the mass of the solvent. $\text{Mass of solution} = \text{Mass of urea} + \text{Mass of water} = 120 \text{ g} + 1000 \text{ g} = 1120 \text{ g}$

Step 3: Calculate the volume of the solution. The volume of the solution can be found using its mass and density. $\text{Volume of solution} = \frac{\text{Mass of solution}}{\text{Density of solution}} = \frac{1120 \text{ g}}{1.15 \text{ g/mL}} = 973.913 \text{ mL}$

Step 4: Convert the volume of the solution to Liters. Since molarity is defined in terms of liters, we need to convert the volume from milliliters to liters. $\text{Volume in L} = \frac{973.913 \text{ mL}}{1000 \text{ mL/L}} = 0.973913 \text{ L}$

Step 5: Calculate the molarity of the solution. Now, we can use the formula for molarity with the values calculated in Step 1 and Step 4. $M = \frac{\text{moles of urea}}{\text{Volume of solution (in L)}} = \frac{2 \text{ mol}}{0.973913 \text{ L}} \approx 2.0535 \text{ M}$

Rounding the result to two decimal places, we get 2.05 M.

Comparing this result with the given options: A: 1.78 M B: 2.00 M C: 2.05 M D: 2.22 M

The calculated molarity matches option C.