How many moles of sodium chloride present in 250 mL of a 0.50 M NaCl solution ?

Options

A. 0.125 mol
B. 0.150 mol
C. 0.075 mol
D. 0.02 mol

Answer

To find the number of moles of sodium chloride (NaCl) in a 250 mL solution with a concentration of 0.50 M, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Molarity Formula**:
The molarity (M) of a solution is defined as the number of moles of solute divided by the volume of the solution in liters. The formula is:
\[ M = \frac{\text{Number of moles}}{\text{Volume of solution in liters}} \]

2. **Convert Volume from mL to Liters**:
Since the volume is given in milliliters (mL), we need to convert it to liters (L) because molarity is expressed in terms of liters.
\[ 250 \, \text{mL} = \frac{250}{1000} \, \text{L} = 0.250 \, \text{L} \]

3. **Use the Molarity to Find Moles**:
Rearranging the molarity formula to find the number of moles gives us:
\[ \text{Number of moles} = M \times \text{Volume in liters} \]
Substituting the values we have:
\[ \text{Number of moles} = 0.50 \, \text{M} \times 0.250 \, \text{L} \]

4. **Calculate the Number of Moles**:
Now we perform the multiplication:
\[ \text{Number of moles} = 0.50 \times 0.250 = 0.125 \, \text{moles} \]

5. **Final Answer**:
Therefore, the number of moles of sodium chloride present in 250 mL of a 0.50 M NaCl solution is:
\[ \text{Number of moles} = 0.125 \, \text{moles} \]