Acids, Carbonates, and Salt Preparation

• Acids, bases, and salts have distinct properties and can be prepared through various chemical reactions.

Properties of Acids

• Acids donate hydrogen ions (H+) or protons during chemical reactions.
• Acids turn litmus paper red.
• Acids react with metals to produce a salt and hydrogen gas: acid + metal -> salt + hydrogen.
• Acids react with carbonates to produce a salt, water, and carbon dioxide: acid + carbonate -> salt + water + carbon dioxide.
• Hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3) are common household acids.

Properties of Bases

• Bases accept hydrogen ions (H+) from other substances.
• Most bases are metal oxides or metal hydroxides, examples include zinc hydroxide [Zn(OH)2] and copper(II) oxide (CuO).
• Bases turn litmus paper blue.
• When a base dissolves in water, an alkali is formed.
• All alkalis are bases, but not all bases are alkalis.
• Neutralization is the reaction between an acid and a base in order to form a salt and water: acid + base -> salt + water.

Properties of Salts

• Salts form when the hydrogen of an acid is replaced by a metal ion or an ammonium ion.
• Salt naming is determined by the acid and base reactants.
• The metal from the base is the first part of the salt's name, and the acid is the second part. Example sulfuric acid + sodium = sodium sulfate
• Salts can be made by reacting an acid with a base, a metal, or a carbonate.
• Crystallization is a common method for forming a solid salt from a solution, and it involves evaporating the water until the salt crystallizes.
• Most salts are solid and crystalline at room temperature, characterized by high melting and boiling points.

Preparation of Soluble Salts using Acid/Base Reactions

• Soluble salts are prepared by reacting an acid with a base through neutralization where acid + base -> salt + water.
• Sulfuric acid and sodium hydroxide create sodium sulfate: H2SO4 + 2NaOH -> Na2SO4 + 2H2O.
• The completion of the reaction is confirmed by the cessation of fizzing or an excess of acid.
• Heating the mixture evaporates water to yield the salt.

Preparation of Soluble Salts using Acid and Carbonates

• Reacting an acid with a metal carbonate or a hydrogen carbonate also produces a soluble salt.
• The general formula is: acid + carbonate -> salt + water + carbon dioxide.
• Hydrochloric acid reacts with sodium carbonate to produce sodium chloride: 2HCl + Na2CO3 -> 2NaCl + H2O + CO2.
• Filtration separates the salt product, where crystallization or evaporation then obtains the salt from the filtrate.

Preparation of Insoluble Salts using Precipitation Reaction

• Precipitation reactions prepare insoluble salts and occur when two solutions containing ions combine to form an insoluble compound.
• Silver nitrate (AgNO3) and sodium chloride (NaCl) produce insoluble silver chloride (AgCl): AgNO3 + NaCl -> AgCl + NaNO3.
• Filtration collects the insoluble salt (precipitate).
• Any remaining ions are then washed away, and the precipitate is dried.

Alternative Preparation of Salts

• Salts can also be prepared by:
  • Direct combination of an element with an element
  • An element with a compound
  • A compound with a compound.
• Combining chlorine gas with sodium metal produces sodium chloride: 2Na(s) + Cl2(g) -> 2NaCl(s).

Explore acid and carbonate reactions, precipitation processes, and salt isolation techniques. Understand the general formula for acid-carbonate reactions and identify byproducts. Match salt preparation methods with their descriptions.