To determine how many moles of KCl would be dissolved in 4 liters of water to create a 2 M solution, we can utilize the relationship between molarity, volume, and moles of solute.
The formula for molarity (M) is given by:
[tex]\[ M = \frac{\text{moles of solute}}{\text{volume of solution in liters}} \][/tex]
Rearranging this equation to solve for moles of solute, we have:
[tex]\[ \text{moles of solute} = M \times \text{volume of solution in liters} \][/tex]
Given:
- Molarity ([tex]\( M \)[/tex]) = 2 M
- Volume of solution = 4 L
We can plug in these values into our equation:
[tex]\[ \text{moles of solute} = 2 \, M \times 4 \, L \][/tex]
[tex]\[ \text{moles of solute} = 8 \, \text{moles} \][/tex]
Therefore, we need 8 moles of KCl dissolved in 4 liters of water to make a 2 M solution.
So, the correct answer is:
B. 8 moles
