To determine the volume of the stock solution needed to make 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 to find
- \(C_2\) = 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 in the known values:
\[ V_1 = \frac{(4.4 , \text{M}) \times (7.6 , \text{L})}{12.4 , \text{M}} \]
Calculating this:
\[ V_1 = \frac{33.44}{12.4} \approx 2.7 , \text{L} \]
The required volume of the stock solution is approximately 2.70 L.
Therefore, the correct response is:
2.70 L