Answer:
1. Zn + HCl --> ZnCl + H2
2. when zinc reacts with hydrochloric acid, the zinc gets oxidized as chlorine is an electronegative element while the hydrochloric acid gets reduced as their is a removal of chlorine from the compound to give out hydrogen
3. it happens in our stomach as it releases hcl in the undigested food to convert it into soluble compounds and waste material for consumption by our body and excretion respectively.