2.  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.
 An Acid is a substance which can accept a pair of
electrons.

3.  Properties of Acids :
 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.

4.  Names and formulae of some important acids are as
follows :
Name of Acids Formulae
1. Hydrochloric Acid HCl
2. Sulphuric Acid H2SO4
3. Phosphoric Acid H2PO4
4. Nitric Acid HNO3

5.  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 printing
press
 Benzoic acid is used for food preservation.
 Acetic acid is used for flavoring food and food flavouring.

6.  A Base is a substance which dissociates in
aqueous solution to give hydroxide ions
 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 electrons.

7.  Sodium Hydroxide is used for manufacturing soap
 Calcium Hydroxide is used for manufacturing of
bleaching powder, softening of hard water and
neutralization.
 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.

8.  Table Base which recognizably :
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

9.  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

 Normal Salts
 Acidic Salts
 Basic Salts
 Double Salts
 Mixed Salts
 Complex Salts

10.  Besides produce from react between acid and
base . Salt also could produce from reaction
others , namely :
1. Base + Metallic Oxide Salt + Water
2. Acid + Metallic Oxide Salt + Water
3. Oxide Acid + Oxide Base Salt
4. Metal + Acid Salt + Hydrogen

11.  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
and detergents.
 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 flint glass.

12.  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 is 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 :

13. Indicators :
 Indicators are organic
compounds. They have
Different colours in
acidic and alkaline
solutions.
 Litmus is a common
indicator
 Red Litmus Turns blue
in base
 Blue Litmus Turns red
in acid
 Each indicator has a
specific colour in
acidic medium which
changes at specific pH
to another colour in
basic medium.