How to prepare 250.0 mL of 0.076M NaOH?
from what? Solid NaOH, from a known stock solution?
Assuming solid NaOH pellets.
determine the mass needed
mass=.250*.076*40 (40 is the formula mass of NaOH)
accurately measure the mass needed.
put 240 ml of distilled H20 in an Erlenmeyer flask, add the solid NaOH.
Put the flask on a stirrer, or hand stir with a glass tube. When disolved, add water to come up to 250 ml.
pour into a storage jar, label, and store properly (away from acids).