The number of moles of the solute present in 500 ml of 0.5M solution is:

Explanation

To find the number of moles of solute present in a 500 ml solution with a molarity of 0.5 M, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the given values**:
- Molarity (M) = 0.5 M
- Volume of solution = 500 ml

2. **Convert the volume from milliliters to liters**:
- Since 1 liter = 1000 ml, we convert 500 ml to liters:
\[ \text{Volume in liters} = \frac{500 \text{ ml}}{1000 \text{ ml/L}} = 0.5 \text{ L} \]

3. **Use the molarity formula**:
- Molarity (M) is defined as:
\[ M = \frac{\text{Number of moles}}{\text{Volume of solution in liters}} \]
- Rearranging the formula to find the number of moles:
\[ \text{Number of moles} = M \times \text{Volume in liters} \]

4. **Substitute the values into the equation**:
- Now, substitute the values of molarity and volume:
\[ \text{Number of moles} = 0.5 \text{ M} \times 0.5 \text{ L} = 0.25 \text{ moles} \]

5. **Conclusion**:
- Therefore, the number of moles of the solute present in 500 ml of a 0.5 M solution is **0.25 moles**.