Dissolving 120 g of a compound of (mol. wt. 60) in 1000 g of water gave a solution of density `1.12 g // mL`. The molarity of the solution is:

Options

A. 1.00 M
B. 2.00 M
C. 2.50 M
D. 4.00 M

Explanation

To find the molarity of the solution, we can follow these steps:

### Step 1: Calculate the mass of the solution
We know that the density of the solution is given as 1.12 g/mL. Since we have 1000 g of water and 120 g of the compound, the total mass of the solution can be calculated as follows:

\[ \text{Mass of solution} = \text{Mass of solute} + \text{Mass of solvent} = 120 \, \text{g} + 1000 \, \text{g} = 1120 \, \text{g} \]

### Step 2: Calculate the volume of the solution
Using the density formula, we can find the volume of the solution:

\[ \text{Density} = \frac{\text{Mass}}{\text{Volume}} \implies \text{Volume} = \frac{\text{Mass}}{\text{Density}} = \frac{1120 \, \text{g}}{1.12 \, \text{g/mL}} = 1000 \, \text{mL} \]

### Step 3: Calculate the number of moles of the solute
To find the number of moles of the solute, we use the formula:

\[ \text{Number of moles} = \frac{\text{Mass of solute}}{\text{Molar mass}} = \frac{120 \, \text{g}}{60 \, \text{g/mol}} = 2 \, \text{moles} \]

### Step 4: Calculate the molarity of the solution
Molarity (M) is defined as the number of moles of solute per liter of solution. Since we found the volume of the solution to be 1000 mL (which is 1 L), we can calculate the molarity:

\[ \text{Molarity} = \frac{\text{Number of moles}}{\text{Volume of solution in L}} = \frac{2 \, \text{moles}}{1 \, \text{L}} = 2 \, \text{M} \]

### Final Answer
The molarity of the solution is **2 M**.

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