Molarity means the number of moles of solute per litre of solution.
The unit is mol L⁻¹
Molarity = moles of solute (mol) / volume of solution (L)
Moles of NaCl = 105 g / 58.5 g mol⁻¹
=1.79 mol
Molarity = 1.79 mol / 0.250 L
Molarity = 7.16 mol L⁻¹