You have 5 kg of water, and add 5 moles of nacl to it. what is the molarity of the solution?

As Molarity is given by,
                                     Molarity = moles / volume     (1)
Data Given:
                   mass of water = 5 Kg = 5000 g
                                moles = 5 moles
Solution:
As we know that volume is related to mass as,
                                     Volume = mass / density
Putting values,
                                     Volume = 5000 g / 1 g/cm³
                                               V = 5000 cm³
Now, Putting value of volume and moles in eq. 1,
                                               M = 5 mol / 5000 cm³
                                               M = 0.0001 mol/cm³
or,
                                               M = 1 mol/dm³

The correct answer is b