10 mL of H2O2 solution (volume strength - x) requires 10 mL of N0.56 MnO4⊝  solution in acidic medium. Hence x is

N of H2O2= Volume strength /5.6=x/5.6 mEq. of H2O2≡mEq. of MnO4⊝∴N1V1≡N2V2x5.6×10mL≡10.56×10mL∴x='10 ' volume strength