The problem is asking for how many moles of water there are in 1 mol of solution with NaCl. This is telling us that NaCl is dissolved in water.
There are 0.132 moles of NaCl and summing the moles of water, we're going to obtain 1 mol of solution. You can see it, like this:
[tex]\text{0}.132\text{ moles NaCl+X moles water = 1 mol solution.}[/tex]
We just have to clear for 'X moles water', and we obtain:
[tex]X\text{ moles water = 1-0.132 = 0.868 moles water.}[/tex]
The answer is that we have 0.868 moles of water in the solution.
