ACIDS
Molecular formula Acid
HCl Hydrochloric acid
HNO3 Nitric acid
H2SO4 Sulphuric acid
CH3COOH Ethanoic acid
BASES / ALKALIS
Base Formula Solubility in water
Copper(II) oxide, CuO Insoluble base
Lead(II) oxide, PbO Insoluble base
Magnesium oxide, MgO Insoluble base
Zinc hydroxide, Zn(OH)2 Insoluble base
Aluminium hydroxide, Al(OH)3 Insoluble base
Sodium oxide, Na2O Soluble base (alkali)
Calcium oxide, CaO Soluble base (alkali)
Sodium hydroxide, NaOH Soluble base (alkali)
Potassium hydroxide, KOH Soluble base (alkali)
Barium hydroxide, Ba(OH)2 Soluble base (alkali)
- Arrhenius acid : An acid is a substance which ionises or dissociates in water to produce hydrogen ions, H+/ hydroxonium ions, H3O+.
- H+(aq) + H2O(l) –> H3O+(aq)
- Example: HCl(aq) + H2O(l) –> H3O+(aq) + Cl-(aq)
Molecular formula Acid
HCl Hydrochloric acid
HNO3 Nitric acid
H2SO4 Sulphuric acid
CH3COOH Ethanoic acid
- Monoprotic acid : acid can produce only one hydrogen ion per molecule in water. (Example: HCl)
- Diprotic acid : acid can produce two hydrogen ions per molecule in water. (Example: H2SO4)
- Triprotic acid : acid can produce three hydrogen ions per molecule in water. (Example: H3PO4)
- Polyprotic acid : acid can produce more than one hydrogen ion per molecule in water.
BASES / ALKALIS
- A base is a chemical substance which reacts with an acid to produce a salt and water only.
- Base(s) + acid(aq) –> salt + water (l).
- Example: NaOH(s) + HCl(aq) –> NaCl(aq) + H2O(l)
Base Formula Solubility in water
Copper(II) oxide, CuO Insoluble base
Lead(II) oxide, PbO Insoluble base
Magnesium oxide, MgO Insoluble base
Zinc hydroxide, Zn(OH)2 Insoluble base
Aluminium hydroxide, Al(OH)3 Insoluble base
Sodium oxide, Na2O Soluble base (alkali)
Calcium oxide, CaO Soluble base (alkali)
Sodium hydroxide, NaOH Soluble base (alkali)
Potassium hydroxide, KOH Soluble base (alkali)
Barium hydroxide, Ba(OH)2 Soluble base (alkali)
Chemical Properties Of Acids and Alkalis
Acid
Alkali
Acid
- In the presence of water, an acid will ionise to form hydrogen ion, H+.
- Sour in taste.
- pH values less than 7.
- Litmus paper : Blue litmus paper turns to red
- Universal indicator : Orange and red
- Methyl orange : Red
- React with bases to produce salts and water.
2HCl(aq) + CuO(s) –> CuCl2(aq) + H2O(l) - React with metals (reactive metal, higher position than H+ in the electrochemical series) to produce salts and hydrogen gas.
2HCl(aq) + Zn(s) –> ZnCl2(aq) + H2(g) - React with carbonates to produce salts, carbon dioxide gas and water.
H2SO4(aq) + ZnCO3(s) –> ZnSO4(aq) + H2O(l) + CO2(g)
Alkali
- In the presence of water, an alkali will ionise to form hydroxide ion, OH -.
- Bitter in taste.
- pH values more than 7
- Litmus paper : Red litmus paper turns to blue
- Universal indicator : Blue and purple
- Methyl orange : Yellow
- React with acids to produce salts and water.
NaOH(aq) + HCl(aq) –> NaCl(aq) + H2O(l) - React with an ammonium salt (alkali is heated) to produce ammonia gas.
Ba(OH)2(aq) + 2NH4Cl(s) –> BaCl2(aq) + 2H2O(l) + 2NH3(g) - React with aqueous salt solutions to produce metal hydroxides (as precipitate).
2NaOH(aq) + CuSO4(aq) –> Na2SO4(aq) + Cu(OH)2(s)
RELATED RESOURCES
- Acids and Bases: An Introduction by Anthony Carpi, Ph.D.
- Acids and Bases are Everywhere by Chem4kids
- Acids
- Bases