Here's how to determine the molarity of a 10 gram NaOH solution in 500 mL:

1. Convert grams of NaOH to moles:

* Molar mass of NaOH: 22.99 g/mol (Na) + 15.999 g/mol (O) + 1.008 g/mol (H) = 39.997 g/mol

* Moles of NaOH: (10 g NaOH) / (39.997 g/mol) = 0.250 mol NaOH

2. Convert milliliters of solution to liters:

* Liters of solution: (500 mL) / (1000 mL/L) = 0.500 L

3. Calculate molarity:

* Molarity (M): (Moles of solute) / (Liters of solution)

* Molarity: (0.250 mol NaOH) / (0.500 L) = 0.500 M

Therefore, the molarity of the solution is 0.500 M.