  We use chiral effective field theory (EFT) to make predictions for the
longitudinal electromagnetic response function of the deuteron, f_L, which is
measured in d(e,e'N) reactions. In this case the impulse approximation gives
the full chiral EFT result up to corrections that are of O(P^4) relative to
leading. By varying the cutoff in the chiral EFT calculations between 0.6 and 1
GeV we conclude that the calculation is accurate to better than 10 % for values
of q^2 within 4 fm^{-2} of the quasi-free peak, up to final-state energies
E_{np}=60 MeV. In these regions chiral EFT is in reasonable agreement with
predictions for f_L obtained using the Bonn potential. We also find good
agreement with existing experimental data on f_L, albeit in a more restricted
kinematic domain.
