2.46 g of sodium hydroxide (molar mass = 40) are dissolved in water and the solution is made to `100 cm^3` in a volumetric flask. Calculate the molarity of the solution.

Answer

To calculate the molarity of the sodium hydroxide (NaOH) solution, we will follow these steps:

### Step 1: Calculate the number of moles of sodium hydroxide (NaOH)
To find the number of moles, we use the formula:

\[ \text{Number of moles} = \frac{\text{mass of solute (g)}}{\text{molar mass (g/mol)}} \]

Given:
- Mass of NaOH = 2.46 g
- Molar mass of NaOH = 40 g/mol

Now, substituting the values:

\[ \text{Number of moles} = \frac{2.46 \, \text{g}}{40 \, \text{g/mol}} = 0.0615 \, \text{moles} \]

### Step 2: Convert the volume of the solution from cm³ to liters
The volume of the solution is given as 100 cm³. To convert this to liters, we use the conversion factor:

\[ 1 \, \text{L} = 1000 \, \text{cm}^3 \]

So,

\[ \text{Volume in liters} = \frac{100 \, \text{cm}^3}{1000} = 0.1 \, \text{L} \]

### Step 3: Calculate the molarity of the solution
Molarity (M) is defined as the number of moles of solute per liter of solution. The formula for molarity is:

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

Substituting the values we calculated:

\[ \text{Molarity} = \frac{0.0615 \, \text{moles}}{0.1 \, \text{L}} = 0.615 \, \text{M} \]

### Final Answer
The molarity of the sodium hydroxide solution is **0.615 M**.

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