Acid is a substance that dissociates in aqueous solution to
give hydrogen ions.
HA H+ + A-
An Acid is a substance (molecule or ion) that can donate
Proton (H+) to another substance.
AnAcid is a substance which can accept a pair of electrons.
• Acids have sour taste. For example, unripe citrus fruits or lemon juice.
• They turn blue litmus red.
• They are corrosive in concentrated form.
• Their aqueous solutions conduct electricity.
• Names and formulae of some important acids are as follows :
Name of Acids Formulae
1. Hydrochloric Acid HCl
2. SulphuricAcid H2SO4
3. Phosphoric Acid H2PO4
4. NitricAcid HNO3
• Sulphuric acid is used to manufacture fertilizers, ammonium
sulphate, explosives, paints, drugs and drugs.
• Nitric acid is used in manufacturing of fertilizers, explosives,
paints and drugs etc.
• Hydrochloric acid is used for cleaning metals, tanning and in
• Benzoic acid is used for food preservation.
• Acetic acid is used for flavoring food and food flavoring.
A Base is a substance which dissociates in aqueous solution to give
BOH B+ + OH-
A Base is a substance that can accept (H+) from another substance.
A Base is a substance (molecule or ion) which can donate a pair of
• Sodium Hydroxide is used for manufacturing
• Calcium Hydroxide is used for manufacturing of
bleaching powder, softening of hard water and
• Potassium Hydroxide is used in alkaline batteries.
• Magnesium Hydroxide is used as a base to
neutralize acidity in stomach.
• Aluminium Hydroxide is used as a foaming agent
in fire extinguishers.
• Ammonium Hydroxide is used to remove grease
stains from cloths.
• Names and formulae of some important Bases are as
Names of Bases Chemical Formulae
1. Sodium Hydroxide NaOH
2. Potassium Hydroxide KOH
3. Calcium Hydroxide Ca(OH)2
4.Aluminium Hydroxide Al(OH)3
• Salts are ionic compounds generally formed by the neutralization of acid with a base.
• Salts are made up of positive and negative ions.
• Its general equation is as follows:
• Acid + Base Salt +Water
• For Example :
HCl + NaOH NaCl + H2O
NaCl is also shown in figure
o Normal Salts
o Acidic Salts
o Basic Salts
o Double Salts
o Mixed Salts
o Complex Salts
Beside the production of Salt from reaction of Acid
and Base, Salts can also be produced by other
reactions, namely :
1. Base + Metallic Oxide Salt +Water
2. Acid + Metallic Oxide Salt +Water
3. OxideAcid + Oxide Base Salt
4. Metal + Acid Salt + Hydrogen
• Sodium Chloride(NaCl) is commonly used as a table salt and for cooking
purposes. It is also used for de-icing roads in winter.
• Sodium Carbonate/Soda Ash(Na2CO3) is used for the manufacture of glass,
detergents, pulps and paper etc.
• Sodium Carbonate/Washing Soda(Na2CO3.10H2O) is used as cleaning agent
for domestic and commercial purposes, for softening of water, in
manufacture of chemicals
• Sodium Sulphate(Na2SO4) It is used for the manufacture of glass, paper
• Sodium Silicate(Na2SiO3) It is used for manufacturing of detergents,
cleaning agents and adhesives
• Sodium Chlorate(NaClO3) It is used for manufacture of explosives plastics
and other chemicals.
• Calcium Chloride(CaCl2) It is used for de-icing roads in winter, as a drying
agent and as freezing agent.
• Potassium Nitrate(KNO3) It is used for fertilizer and for the manufacture of
• pH is a measure of hydrogen ion concentration; a measure of the acidity or alkalinity of a
solution.Aqueous solutions at 25°C with a pH less than seven are acidic, while those with a
pH greater than seven are basic or alkaline.A pH level of 7.0 at 25°C is defined as ‘Neutral’.
• pH is the negative logarithm of molar concentration of Hydrogen ions.
• pH = -log[ H+ ]
• with reference to this equation , a scale develops to the molar concentration of H+ ions
that is called pH scale.
• A pH scale is shown below :
• Indicators are organic compounds.
They have Different colours in acidic
and alkaline solutions.
• Litmus is a common indicator
• Red LitmusTurns blue in base
• Blue LitmusTurns red in acid
• Each indicator has a specific colour
in acidic medium which changes at
specific pH to another colour in