Molarity is defined as the number of moles dissolved in 1 L of solution.
The molarity of KCl has been given as 4.0 M
This means that in 1 L of KCl solution, there are 4 moles dissolved.
We have been asked to find the volume of the solution if there are 8.0 moles of solute.
If 4 moles are in - 1 L of solution
Then 8 moles of solute are in - 1/4 x 8 = 2 L solution
Volume of KCl solution is 2 L.