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:
\[ \text{Molarity (M)} = \frac{\text{moles of solute}}{\text{volume of solution in liters}} \]

### Step 2: Find the density and convert it to mass
We are given the density of the solution as \(1.37 \, \text{g/mL}\). To find the mass of 1 liter of solution:
\[ \text{Mass} = \text{Density} \times \text{Volume} \]
Since 1 liter = 1000 mL:
\[ \text{Mass} = 1.37 \, \text{g/mL} \times 1000 \, \text{mL} = 1370 \, \text{g} \]

### Step 3: Calculate the number of moles of solute
We know the molecular weight of the solute is \(68.5 \, \text{g/mol}\). To find the number of moles:
\[ \text{Moles} = \frac{\text{Mass}}{\text{Molecular Weight}} \]
Substituting the values:
\[ \text{Moles} = \frac{1370 \, \text{g}}{68.5 \, \text{g/mol}} \]

### Step 4: Perform the calculation for moles
Calculating the above gives:
\[ \text{Moles} = 20 \, \text{mol} \]

### Step 5: Calculate the molarity
Now, we can substitute the number of moles and the volume of the solution into the molarity formula:
\[ \text{Molarity} = \frac{20 \, \text{mol}}{1 \, \text{L}} = 20 \, \text{M} \]

### Final Answer
The molarity of the solution is \(20 \, \text{M}\).

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