Answer
See answers.
Work Step by Step
Charge must be conserved, so a neutron cannot simply change into a proton via a strong nuclear interaction. When the neutron decays, it produces a proton, an electron, and an antineutrino. As discussed on page 930, electrons and neutrinos are leptons, and do not interact via the strong nuclear force. In particular, the antineutrino must be the product of a decay mediated by the weak interaction (i.e., the neutron decays via the weak interaction).
When a neutron is inside a stable nucleus, the strong nuclear forces between it and other nucleons are dominant. It is only when it is neutron is free that the weak interaction can cause the neutron’s decay.