  We examine bulk viscosity, taking into account trapped neutrinos in baryonic
matter, in the context of binary neutron star mergers. Following the merging
event, the binary star can yield a remnant compact object with densities up to
$5$ nuclear saturation density and temperature upto $50$ MeV resulting in the
retention of neutrinos. We employ two relativistic mean field models, NL3 and
DDME2, to describe the neutrino-trapped baryonic matter. The dissipation
coefficient is determined by evaluating the Modified URCA interaction rate in
the dense baryonic medium, and accounting for perturbations caused by density
oscillations. We observe the resonant behavior of bulk viscosity as it varies
with the temperature of the medium. The bulk viscosity peak remains within the
temperature range of $\sim 13-50$ MeV, depending upon the underlying equation
of states and lepton fractions. This temperature range corresponds to the
relevant domain of binary neutron star mergers. We also note that in presence
of neutrinos in the medium the bulk viscosity peak shifts towards higher
temperature and the peak value of bulk viscosity also changes. The time scale
of viscous dissipation is dictated by the beta-off-equilibrium susceptibilities
derived from the nuclear equation of state. The resulting viscous decay time
scale ranges from $32-100$ milliseconds, which aligns with the order of
magnitude of the post-merger object's survival time in some specific scenarios.
