if we have 6.68% NaClO, it is the same as saying--> 6.68 grams NaClO= 100 mL of solution. we can use this as a conversion.
800. mL (6.68 mL/ 100 mL)= 53.4 mL
solution = solute + solvent
solute= NaClO
solvent= H2O
solvent= 800-53.4= 747 mL of H2O
so, we you need 53.4 mL of NaClO and 747 mL of water or 53.4 grams of NaClO and 747 mL of water