The volume of 0.08892 M HNO3 required to react completely with 0.2352g K2HPO4 is 0.0304 Liters
calculation
find the moles of K2HPO4 reacted
moles=mass/molar mass
=0.2352 g/174 g/mol = 1.35 x10^-3 moles
By use of mole ratio of HNO3: K2HPO4 which is 2:1 the moles of HNO3 is therefore = 1.35 x10^-3 x2 =2.7 x10^-3 moles
Volume of HNO3=moles/molarity
=2.7 x10^-3/0.08892= 0.0304 Liters