Final answer:
The reaction Mn + H2O → H2 + Mn(OH)3 is an example of a single replacement reaction, where manganese displaces hydrogen from water.
Step-by-step explanation:
The reaction shown, Mn + H₂O → H₂ + Mn(OH)₃, is categorized as a single replacement reaction. In this type of reaction, one element (in this case, Mn) displaces another in a compound (H from H₂O) to form a new element (H₂) and a new compound (Mn(OH)₃). It is part of a larger subcategory known as metal replacement, since it involves the replacement of a metal ion in a compound with a free metal. For further understanding, looking at other reactions like Mg(s) + Cu(NO₃)₂ (aq) → Mg(NO₃)₂ (aq) + Cu(s), we observe the same pattern where one metal replaces another.