Final answer:
The molarity of a 0.25 L solution containing 12 g of NaOH is calculated by first determining the number of moles of NaOH, which is 0.3 moles, and then dividing by the volume of the solution, resulting in a molarity of 1.2 M NaOH.
Step-by-step explanation:
The molarity of a solution is the number of moles of solute per liter of solution. To calculate the molarity, you first need to determine how many moles of the solute, in this case sodium hydroxide (NaOH), are present. The molar mass of NaOH is approximately 40 g/mol. Thus, 12 g of NaOH is equivalent to 0.3 moles (12 g ÷ 40 g/mol).
With the volume of the solution provided as 0.25 liters (L), you can calculate the molarity by dividing the number of moles by the volume of the solution in liters:
Molarity = 0.3 moles NaOH / 0.25 L = 1.2 M NaOH