What volume of 0.2535 M NaOH required to titrate 0.8508 g of KHP to stoichiometric end point?
First you need to write out the balanced equation to determine the mole ratio between C8H5KO4(aq) and NaOH(aq)
The chemical formula for KHP is C8H5KO4
NaOH + C8H5KO4-->NaC8H4KO4 + H2O
Because the ratio between C8H5KO4 and NaOH is one to one you will need the same number of moles of NaOH as KHP to reach the equivalence point. So the steps are grams KHP to moles KHP to mmol KHP to mmol NaOH to ml NaOH as your final answer:
0.8508 g KHP(1mol/204.22g)(1000mmol/1mol)(1mmol NaOH/1mmol KHP)(1ml NaOH/0.2535mmol)= 16.43ml