Acids, Bases & Salts

Common acids:

• Hydrochloric Acid- HCL
• Nitric Acid- HNO₃
• Sulphuric Acid- H₂SO₄

Acid: species that is a proton donor eg the H+

In water acids give a pH of less than 7.0

Common bases are metal oxides and hydroxides

eg MgO, CuO and NaOH, Mg(OH)₂

Ammonia is also a common base- NH₃   

Hydroxides like calcium hydroxide are used for treating acid soils as they neutralise acids.

A base is a proton accepetor

An alkali that has a pH greater than 7.0

Common alkalis:

• Sodium Hydroxide- NaOH
• Potassium Hydroxide- KOH
• Ammonia- NH₃    

An alkali is a type of base that dissolves in water forming OH− ions

A salt is an ionic compound where a H+ is replaced with a metal or positive ion.

example:

H₂SO(sulphuric acid) goes to K₂SO (potassium sulphate)

Salts can be formed by neutralising acids with carbonates, bases and alkalis

From carbonates: Acid + carbonate → Salt + Carbon Dioxide + Water

Example; 2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂

From bases: Acid + Bases → Salt + Water

Example; 2HCl + CaO → CaCl₂ + H₂O

From Alkalis: Acid + Alkalis→ Salt + Water

HCL + NaOH → NaCl + H₂O

Salts can be also formed from metals 

Metal + Acids  →  Salt + hydrogen gas

Example; Mg + 2HCL  →  MgCl₂ + H₂