This document discusses acids, bases, and salts. It defines acids as hydrogen-containing substances that can donate protons, and bases as substances that can accept protons and produce hydroxide ions in aqueous solutions. Strong acids fully dissociate in water while weak acids only partially dissociate. Common strong acids include sulfuric acid and hydrochloric acid. Common strong bases include sodium hydroxide and calcium hydroxide. Salts are formed when acid protons are replaced by metal ions. Salts have various properties and uses such as in batteries, fertilizers, and medicine. The document also explains the pH scale for measuring acidity and basicity.

1. ACIDS, BASES & SALTS
Pranabjyoti Das

2. Acids
Introduction :
An acid is any hydrogen containing
substance that is capable of donating
a proton or hydrogen Ion to another
substance.
Arrhenius definition:
Any substance that, when dissolved in water,
increases the concentration of hydronium ion
(H3O+) is called as Acid
Thus acids are proton donors or electron
acceptors.
Example : H2SO4, HCl, CH3COOH

3. Properties ofacids
They taste sour. The word 'acid' comes from the Latin
“acere”, which means 'sour'
Acids can change litmus from blue to red
Aqueous solutions of acids canconduct electric
current
Acids react with bases to form salts and water
Acids can release H2 upon reaction with an active metal
such as zinc, aluminum etc

4. Classification of acids:
Strong Acid:
They break down completely to give off many H+ ions in
their aquous state

5. Weak Acids:
They partially breaks down, gives less number
of H+ in their aquous solutions

6. Some Common Acids
Strong Acids The Formula
Sulphuric acid H2SO4
Hydrochloric acid HCl
Hybrobromic acid HBr
Hydroiodic acid HI
Nitric acid
Perchloric acid
HNO3
HClO4
Some weak Acids are …
Weak Acid The Formula
Acetic acid(vinegar)
Carbonic acid
CH₃COOH
H₂CO₃

7. Uses of Acids
Acids have numerous uses, some of which
include:
HCl in stomach
H2SO4 in car batteries, asdryingagent’
HNO3 in manufacturing of fertilizers
Ethanoic acid in food industry
Fatty acids in soap making
Ascorbic acid in medicine

8. Bases
Bases produce OH- ions in aqueoussolutions.
Bases are proton acceptors
Bases are electron pairdonors
Least restrictive of acid-basedefinitions
Examples of Bases:
NaOH, Mg(OH)2, Ca(OH)2.

9. Properties of Bases
Bases taste bitter
Bases are slippery or soapy to touch
Bases can turn acidified red litmus to blue
Their aqueous solutions conduct electric current
Bases react with acids to form salts andwater

10. Classification of Bases
Strong bases:
A strong base is a basic chemical compound that can release hydroyl
ions in maximum amount. Common examples of strong bases include
hydroxides of alkali metals and alkaline earth metals like NaOH and
Ca(OH)2
Strong Bases Formulae
Potassium hydroxide (KOH)
Barium hydroxide (Ba(OH)2)
Cesium hydroxide (CsOH)
Sodium hydroxide (NaOH)
Strontium hydroxide (Sr(OH)2)
Calcium hydroxide
Lithium hydroxide
(Ca(OH)2)
(LiOH)
Rubidium hydroxide (RbOH)

11. Weak Bases
A weak base is a basic chemical compound that can
release hydroyl ions in less amount. Common example of
weak base is NH4OH
Strong Bases Formulae
Ammonia NH3
Methylamine CH3NH2
Pyridine C5H5N
Ammonium hydroxide NH4OH

12. Preparation of Bases
There are various methods for the preparation ofbases.
Reaction of oxygen with metals to form metal oxide:
Many metals react with oxygen gas to form the metal oxide.
Forexample, calcium reacts in the following manner.
2Ca(s) + O2(g) 2 CaO(s)
Thermal decomposition of carbonates:
Metal carbonates such as calcium carbonate break down when
heated strongly. This is called thermal decomposition. Here
are the equations for the thermal decomposition of calcium
carbonate:
CaCO3 ―> CaO +CO2

13. By double decomposition reaction:
A chemical reaction between two compounds in which
parts of each are interchanged to form two new
compounds
(AB + CD = AD + CB)
By dissolving basic oxides in water:
The oxides of feebly acidic cations react exothermically
with water
producing the hydroxide.
CaO + H2O ‹―› Ca(OH)2

14. Uses of Bases:
 Sodium hydroxide (caustic soda) is used in the manufacture of
soap. It is used in petroleum-refining; in making medicines,
paper, pulp, etc. It is used in making rayon.
 Calcium hydroxide is also known as slaked lime. It is used to
neutralize acid in water supplies; in the manufacture of
bleaching powder; as a dressing material for acid burns; as an
antidote for food poisoning; in the preparation of fungicides
and in the mixture of whitewash. It is mixed with sand and
water to make mortar which is used in the construction of
buildings. It is also used by farmers on the fields to neutralize
the harmful effects of acid rain.
 Ammonium hydroxide is used toremove ink spots from clothes
and to remove grease from window-panes. It is used in the
cosmetic industry.
 Alkalis are used in alkaline batteries. Generally potassium
hydroxide is used in such batteries.

15. Salts
+ 2NaOH(aq) ==== Na2SO4(aq) +
H2SO4(aq) 2H2O(l)
Here sodium sulphate (Na2SO4) is the salt formed.
The chemical symbol for table salt isNaCl
When H+ ion of an acid is replaced by a metal ion, a
salt is produced

16. Properties of salts
Most of the salts are crystallinesolid.
Salts may be transparent oropaque.
Most of the salts are soluble inwater.
Solution of salts conducts electricity.
Salts conduct electricity intheir molten statealso.
The salt may be salty, sour, sweet and bitter
Neutral salts areodourless.
Salts can be colourless or ofcoloured.

17. Classification of Salts
1.Normal salt The hydrogen ions of the acid are completely
replaced by metallic ions . Examples are NaCl, CuSO4, KNO3,
and CaCO3. Normal salts are electrically neutral.
2.Acid salt The salt still has hydrogen atom(s) from an acid
which can further be replaced by metallic ions. Examples
include: NaHSO4, NaHCO3 etc
3.Basic salt The salt contains hydroxides together with
metallic ions and negative ions from an acid. Examples are
basic zinc chloride, ZnOHCl, basic magnesium chloride etc
There are different kinds of salts. Theseinclude:

18. Uses of Salts
S.No Salt Use
1 Ammonium Chloride In torch batteries
2 Ammonium Nitrate In fertilizers
3 Calcium Chloride As drying agent
4 Iron Sulphate In Iron tablets
5 Magnesium Sulphate In medicine
6 Potassium Nitrate In gunpowder etc.
7 Silver Bromide In photography
8 Sodium Chloride Making NaOH
9 Sodium Stearate In making soap.

19. pH Scale
The negative logarithm of the hydronium ion concentration of an
aqueous solution; used to express acidity.
pH is the measure of the acidity
or basicity of a solution. The pH scale
ranges from 1 to 14
1 through 6 being acidic
7 is considered neutral
8 through 14 being basic

20. pH is a way to measure how acidic
or basic a solution is.
Low pH values = Acids
High pH values = Bases
pH measures the concentration
of hydrogen ions = H+