How many kg of wet NaOH containing 12% water are required to prepare 60 litre of 0.5N solution?

Answer 1

Let's assume for the moment the water is not there.
How many mols do we want. That is M x L = mols = 0.5 x 60 = ? (I've used molarity since mols and equivalents for NaOH are the same).
How many grams is that?
grams = mols x molar mass IF IT WERE PURE STUFF BUT IT'S ONLY 100-12 = 88% NaOH. Therefore, we need grams from above/0.88 = grams of the wet stuff.