To determine the volume of the stock solution needed to create a diluted solution, you can use the dilution equation:
\[ C_1 V_1 = C_2 V_2 \]
Where:
- \( C_1 \) = concentration of the stock solution (12.4 M)
- \( V_1 \) = volume of the stock solution needed
- \( C_2 \) = concentration of the diluted solution (4.4 M)
- \( V_2 \) = volume of the diluted solution (7.6 L)
Rearranging the equation to solve for \( V_1 \):
\[ V_1 = \frac{C_2 V_2}{C_1} \]
Substituting the values into the equation:
\[ V_1 = \frac{(4.4 , \text{M})(7.6 , \text{L})}{12.4 , \text{M}} \]
Calculating:
\[ V_1 = \frac{33.44 , \text{M}\cdot\text{L}}{12.4 , \text{M}} \] \[ V_1 \approx 2.70 , \text{L} \]
Therefore, the correct answer is:
2.70 L