A single-replacement reaction, a single-displacement reaction, is a reaction by which one (or more) element(s) replaces an/other element(s) in a compound.
It is most often occur if element is more reactive than the other, thus giving a more stable product.
In this reaction, zinc metal (more active) displaces the hydrogen to form hydrogen gas and zinc chloride, a salt. Zinc reacts quickly with the acid to form bubbles of hydrogen.
<u><em>Reaction 7:</em></u> N₂O₅ + H₂O → 2HNO₃.
It is a combination "synthesis" reaction.
A synthesis reaction has two or more reactants and only one product.
In this reaction, dinitrogen pentoxide reacts with water to produce nitric acid.
So, it is considered as a synthetic "combination" reaction.
