Describe the preparation of 500 ml of 0.25 M solution of NaOH from NaOH pellets (88% purity).

Answer 1

molarity=mass/(molemass*volume)

mass=.25*40*.5
but that would be mass of pure NaOH.
massimpure=masspure/.88
so take that amount of pellets, add water to the 500ml mark while stirring, label and store.
Safety: wear goggles and gloves.