Consider the following enthalpy changes: F2(g) + HF(g) FHF2(g) ÎH = 155 kJ/ mol H2O(g) + HOH(g)

Question:

Consider the following enthalpy changes:
F2(g) + HF(g) †’ FHF2(g) Î”H = €“155 kJ/ mol

H2O(g) + HOH(g) †’ H2O---HOH (in ice) Î”H = €“21 kJ/ mol
How do the strengths of hydrogen bonds vary with the electronegativity of the element to which hydrogen is bonded? Where in the preceding series would you expect hydrogen bonds of the following type to fall?