Among NH₃, H₂O and HF, which would you expect to have the highest magnitude of hydrogen bonding and why ?

All these molecules exhibit hydrogen bonding due to the presence of highly electronegative atom N, O and F.

Electronegativity of N, O F increases as N < O < F.
Therefore strength of hydrogen bond also increases as
N - H ... N < O - H ... O < F - H ... F
In other words, the magnitude of the +ve charge on hydrogen and -ve charge on F is highest and hence electrostatic attraction or hydrogen bonding is strongest in H – F.