How do you calculate molarity of NaOH?

molarity = # mols/L.

If you have grams, moles = grams/molar mass

molarity x liters = moles

you would need to know how many moles or liters to use the above formula. How much NAOH are you being asked to find molarity for?

To calculate the molarity (M) of a solution, you need to know the amount of solute (in moles) and the volume of the solution (in liters). Here's how you can calculate the molarity of NaOH:

1. Determine the amount of NaOH in moles:
You need to know the mass of NaOH and its molar mass. The molar mass of NaOH is the sum of the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). The atomic mass of sodium is 22.99 g/mol, oxygen is 16.00 g/mol, and hydrogen is 1.01 g/mol. So, the molar mass of NaOH is 22.99 + 16.00 + 1.01 = 40.00 g/mol.
Divide the mass of NaOH you have by the molar mass to get the amount in moles. Let's say you have 5 grams of NaOH, then the amount in moles would be 5 g / 40.00 g/mol = 0.125 moles.

2. Determine the volume of the solution in liters:
You need to know the volume of the solution in which the NaOH is dissolved. This could be given in the problem or you may need to measure it. Let's say the volume of the solution is 0.25 liters.

3. Calculate the molarity:
Divide the amount of NaOH in moles by the volume of the solution in liters. Using the values from above, the molarity is 0.125 moles / 0.25 L = 0.5 M.

So, the molarity of NaOH in the given solution is 0.5 M.