Question

Describe how you can prepare 0.25 molar solution of sodium hydroxide from an 80 percent stock solution in a 500mls beaker

Answer 1

80% what. I presume you mean 80% w/v .
80% w/v solution NaOH means 80 g NaOH/100 mL solution. mols NaOH in 80g is mols = grams/molar mass = 80/40 = 2 mols. 2 mols/100 mL solution = 2mol/0.1L = 20 M
mL1 x M1 = mL2 x M2
500mL x 0.25M = mL2 x 20

Solve for mL2, place that amount of the stock solution in a 500 mL volumetric flask and make to the mark. Mix thoroughly.