A base is a substance which reacts with an acid to form salt and water. Bases are normally oxides and hydroxides. Examples of bases include calcium oxide, CaO, and iron (ii) hydroxide, Fe(OH)2.
The first equation: HNO3(aq) + NaHCO3(aq) --> NaNO3(aq) + H2O(l) + CO2(g)
A salt is formed when hydrogen ions in an acid are replaced by metal ions or ammonium ions, for example, NH4Cl, NaSO4, KNO3, and K3PO4. These salts are classified into two groups: normal salts and acidic salts.
A normal salt is a salt in which all of the acid hydrogen atoms have been replaced by a metal or the hydroxide radicals of a base are replaced by an acid radical, for instance, NaHCO3. (Encyclopedia)
The second equation: 2Fe(s) + 3Br2(l) --> 2FeBr3(s)
The method chosen to prepare a salt is determined by its solubility. One method of preparing soluble salts like binary salts such as 2FeBr3, FeCl2 and AlCl3, is a direct combination. Direct combination reactions result in binary salts. Binary salts are salts that are made up of only TWO types of elements. For example, the preparation of 2FeBr3 --> 2Fe(s) + 3Br2(l).