Answer
0.025 L of that solution contains 0.100 mole of $KCl$
Work Step by Step
1. Since the molarity of that solution is equal to $ 4.00 \space M \space KCl$:
$1 \space L \space solution = 4.00 \space moles \space KCl$
$\frac{1 \space L \space solution}{ 4.00 \space moles \space KCl} $ and $\frac{ 4.00 \space moles \space KCl}{1 \space L \space solution}$
2. Use the conversion factors to calculate the volume of that solution that has 0.100 mole $KCl$:
$0.100 \space mole \space KCl \times \frac{1 \space L \space solution}{ 4.00 \space mole \space KCl} = 0.025 \space L \space solution$
