Statement I ;   Both O -H  Bond enthalpy values in Water  Molecule are equalStatement II : H–H bond length is equal to D–D bond length

Bond enthalpy values depend on chemical environment… Both O–H bond enthalpy values are different in waterH2Og → HOg+Hg;   ΔH1 = 502kJHOg → Hg+Og;  ΔH2 = 427kJΔH1 ≠  ΔH2Protium and Deuterium are isotopes of same element. They have same size.∴ H–H B. L = D–D B.L = 74 pm