A neutralisation reaction occurs when an acid reacts with a base. A salt and water are the end products of this reaction. An acid–base neutralisation reaction is formulated as a double-replacement reaction in this standard approach.
Reactions of acids and bases
a) Reaction of acids and bases with metals
Acids, in general, react with metals to produce salt and hydrogen gas. Bases, in general, do not react with metals and do not produce hydrogen gas.
Acid + active metal → salt + hydrogen + heat
2HCl + Mg → MgCl2 + H2 (↑)
Hydrochloric acid + Magnesium → Magnesium chloride + Hydrogen
Base + metal → salt + hydrogen + heat
2NaOH + Zn → Na2ZnO2 + H2 (↑)
Sodium hydroxide + Zinc → Sodium zincate + Hydrogen
A more reactive metal displaces the less reactive metal from its base.
2Na + Mg (OH) 2 → 2NaOH + Mg
Sodium + Magnesium hydroxide → Sodium hydroxide + Magnesium
b) Reaction of acids with metal carbonates and bicarbonates
Acids produce carbon dioxide, as well as metal salts and water, when they react with metal carbonates or metal bicarbonates. Sodium chloride, carbon dioxide, and water are formed when sodium carbonate interacts with hydrochloric acid. Allowing carbon dioxide gas to travel through lime water turns it milky.
Acid + metal carbonate or bicarbonate → salt + water + carbon dioxide.
2HCl + CaCO3 → CaCl2 + H2O + CO2
H2SO4 + Mg (HCO3)2 → MgSO4 + 2H2O + 2CO2
Effervescence indicates liberation of CO2 gas.
c) Reaction of Acid with Base
1. Reaction of metal oxides and hydroxides with acids
Metal oxides or metal hydroxides are basic in nature.
Acid + base → salt + water + heat
H2SO4 + MgO → MgSO4 + H2O
2HCl + Mg (OH) 2 → MgCl2 + 2H2O
2. Reaction of non-metal oxides with bases
Non-metal oxides are acidic in nature
Base + Nonmetal oxide → salt + water + heat
2NaOH + CO2→ Na2CO3 + H2O
3. Reaction of acids and base
A very common acid is hydrochloric acid. The reaction between strong acid says hydrochloric acid and strong base say sodium hydroxide forms salt and water. The complete chemical equation is shown below.
HCl (strong acid) + NaOH (strong base) → NaCl (salt) + H2O (water)
Water
Acids and bases in water
When added to water, acids and bases dissociate into their respective ions and help in conducting electricity.