An aqueous solution has a density of `1. 37 g//ml`. If molecular wt of solute is `68.5 g//mol`, then calculate molarity of solution.

Options

A. `2 M`
B. `50 M`
C. `5 M`
D. `20 M`

Explanation

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

### Step 1: Understand the formula for molarity
Molarity (M) is defined as the number of moles of solute per liter of solution. The formula is:
\[ M = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]

### Step 2: Calculate the number of moles of solute
The number of moles can be calculated using the formula:
\[ \text{Number of moles} = \frac{\text{mass of solute (g)}}{\text{molar mass (g/mol)}} \]

### Step 3: Find the mass of solute in 1 liter of solution
Given the density of the solution is \(1.37 \, \text{g/mL}\), we can find the mass of 1 liter (1000 mL) of the solution:
\[ \text{Mass of solution} = \text{Density} \times \text{Volume} = 1.37 \, \text{g/mL} \times 1000 \, \text{mL} = 1370 \, \text{g} \]

### Step 4: Calculate the mass of the solute
To find the mass of the solute, we need to know the mass of the solvent (water) in the solution. Assuming the solution is mostly water, we can use the molar mass of the solute to find the mass of the solute. However, without the mass of the solvent, we can directly use the total mass of the solution to find the moles of solute.

### Step 5: Calculate the number of moles of solute
Using the molar mass of the solute, which is \(68.5 \, \text{g/mol}\):
\[ \text{Number of moles of solute} = \frac{\text{mass of solute}}{\text{molar mass}} = \frac{1370 \, \text{g}}{68.5 \, \text{g/mol}} \approx 20.00 \, \text{mol} \]

### Step 6: Calculate the molarity
Now, we can calculate the molarity using the number of moles and the volume of the solution in liters:
\[ M = \frac{20.00 \, \text{mol}}{1 \, \text{L}} = 20.00 \, \text{M} \]

### Final Answer
The molarity of the solution is approximately \(20.00 \, \text{M}\).

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