50% purity NAOH liquid . if the density is 1.53 . so one liter hou much NAOH is here ?

density is given by mass/volume

so if the density is 1.53 g/L then we rearrange the formula to find the mass which just happens to be 1.53grams due to there only being 1 litre

so depending on whether the question is asking for how many moles of NAOH or how many grams of pure NAOH.

another way to look at it, is that if the solution is 50% NAOH then the volume of NAOH in the solution has to be 500mL so u can put that into the density equation and use that value

it is probably best for you to finish this off yourself, hope it helped :)