The document discusses various theories defining acids and bases, namely the traditional, Arrhenius, Bronsted-Lowry, and Lewis theories, explaining their characteristics and limitations. It also covers the properties, preparation, and uses of specific acids and bases including hydrochloric acid, boric acid, ammonium hydroxide, calcium hydroxide, and sodium hydroxide. Additionally, the document addresses the concept of buffer solutions and relevant examination questions.

1. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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CHAPTER 1 ACIDS, BASES, BUFFERS
Acids, Bases are defined by four main theories
1. Traditional theory / concept
2. Arrhenius theory
3. Bronsted and Lowry theory
4. Lewis theory
1. Traditional theory / concept
 Acid : are the substance
o Which converts blue litmus paper to red
o Having the PH < 7
o Sour Taste
o React with bases to form salts and Water
o Eg :- Hydrochloric acid (HCl)
 Base : are the substance
o which converts red litmus paper to blue
o Having the PH >7
o Bitter taste
o React with Acids to form salts and water
o Eg: Sodium Hydroxide (NaOH)
2. Arrhenius theory*
 In 1884 of Svante Arrhenius Also known as, Arrhenius theory of
ionization
 Electron dissociation theory
 This theory define acids & bases according to their formation of ions
when dissolved in water
 An Acid is a substance that can release hydrogen ion (H+
) when dissolved
in water or A substance which when dissolved in water gives hydrogen
ions (H+
) is known as acid
E.g. Hydrochloric acid (HCl)

2. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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 A Base is a substance that can release a Hydroxyl ion (OH-
) when
dissolved in water Or A substance which when dissolved in water gives
Hydroxyl ion (OH-
)is known as Base
Eg: Sodium Hydroxide [NaOH]
 Neutralization reaction :
o Acids react with Base and form Salt & Water
o Eg: Hydrochloric acid react sodium hydroxide and form Sodium
chloride (Salt) & water
NaOH + HCl = NaCl + H2O
(BASE) + (ACID) = (SALT) + (WATER)
 Limitation of Arrhenius theory
o Water is essential
o Not explain Acidity or Basisity of non aqueous Solvent Eg :Benzene
o Basisity of Ammonia (No OH-
ion) is not explained
o Acidity of BF3,AlCl3 (No H+
ion) is not explained
3. Bronsted and Lowry theory
 Bronsted in Copenhagen and Lowry in London independently in 1923
proposed simultaneously new definition of acid and base
 Acid: is a substance that can donate a proton i.e. acid is a proton donor.
 Base: is a substance that can accept a proton i.e. base is a proton acceptor.

3. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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4. Lewis theory
 One of the simplest bonding theories was developed by G.N. Lewis and
is called Lewis Theory.
 Acid: is a molecule or ion that can accept a lone pair of electrons.
 Base: is a molecule or ion that has a lone pair of electrons which is
donated.
 Strong & Weak Acid and Base
o Strong Acid: Produce more amounts of H+
ions in water. E.g. HCl
o Weak Acid: Produce fewer amounts of H+
ions in water. E.g. CH3COOH
o Strong Base: Produce more amounts of OH-
ions in water. E.g. NaOH
o Weak Base: Produce fewer amounts of OH-
ions in water. E.g. NH4OH
Acids Bases
Strong Weak Strong Weak
HCl CH3COOH NaOH NH4OH
H2SO4 HCN KOH NaHCO3
NHO3 C6H5COOH CaO C6H5NH2
HCIO4 HCOOH Na2CO3 CH3NH2
HCIO3 H2CO3 - -
HBr C6H5OH - -
HI - - -

4. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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 Buffer Solution
o It is capable to resist / appose / prevent the change in pH or pOH
value when adding in small amount of acid & base.
 Types of Buffer Solutions
o Acidic Buffer: solution contains weak acid and salt known as acidic
buffer.
o Basic Buffer: solution contains weak base and salt known as basic
buffer.
 pH and pOH
o pH : - log
o pOH : - log
o Therefore pH + pOH = 14
7 + 7 = 14
Some Official Acids & Bases
 Acids
o Boric Acid [H3BO3]
o Hydrochloric Acid [HCl] Conc. & Dil
 Bases
o Strong Ammonium Hydroxide [NH4OH]
o Calcium Hydroxide [Ca(OH)2]
o Sodium Hydroxide [NaOH]

5. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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Boric Acid: (H3BO3)
o Synonym : Boracic Acid , Orthoboric Acid
o Limit: It contains not less than 99% & not more than 100.5% of H3BO3.
o Preparation: Borax with Sulphuric acid in presence of water.
Na2B4O7 + H2SO4 + 5H2O = 4H3BO3 + Na2SO4
o Properties:
 White crystalline powder.
 Odorless.
 Insoluble in water.
 Soluble in Ethanol.
 Soluble in glycerin.
o Uses:
 Local anti-infective.
 To maintain acidic pH medium in Medicament.
 Preparation of buffer solution.
 In ophthalmic preparation.
 Dusting powder.
 Preparation of ointment.
Conc. Hydrochloric Acid [HCl]
o Synonym : Muriatic Acid
o Limit: It contains not less than 35% and not more than 38% of HCl.
o Preparation: Conc Sulfuric acid reacts with sodium chloride.
NaCl + H2SO4 = HCl + NaHSO4
o Properties:
 Clear Colorless Liquid.
 Pungent Odor.
 Miscible with water and alcohol.
 Fuming liquid.
o Uses:
 As a Pharmaceucal Aid (Afacidifying Agent)
 As a solvent in Industry
 As a reagent in Laboratory
 For manufacturing of basic Pharmaceuticals.
o Storage: temp not exceeding 30 C in a glass stopped container.

6. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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Dil. Hydrochloric Acid [HCl]
o Synonym , Limit, Properties, uses and storage same as Conc.
Hydrochloric Acid [HCl]
o Preparation: 10 ml Conc. HCl + up to 100 ml Water.
Strong Ammonium Hydroxide [NH4OH]
o Synonym : Ammonium hydroxide, strong ammonium water, liquor
ammoniae forties
o Limit: It contains not less than 25% of ammonia.
o Preparation: By mixing ammonium chloride with slaked lime.
NH4Cl + Ca(OH)2 =NH4OH + CaCl2
o Properties:
 Clear colorless liquid
 Pungent odor
 Characteristic taste
 Miscible with water
 Aqueous solution is strongly
 Alkaline in nature.
o Uses:
 Alkalizing agent
 Reflux stimulant (fainted person)
 Vasoconstrictor
 Strong base
 Antacid
 Reagent in Laboratory.
o Storage: temp store in umber color bottle with rubber stopper.

7. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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Calcium Hydroxide [Ca(OH)2]
o Synonym : Slaked Lime, Lime water
o Preparation: By treating calcium chloride with sodium hydroxide.
CaCl2 + 2NaOH = Ca(OH)2 + 2NaCl
o Properties:
 White amorphous powder,
 Slight bitter taste,
 Slightly soluble in Water,
 Insoluble in Alcohol
 Soluble in Glycerin.
o Uses:
 Antacid
 Astringent
 Fluid electrolyte
 Emulsifying agent
 Absorb carbon dioxide
 Making of glass
 White washing of cloth.
Sodium Hydroxide [NaOH]
o Synonym : Caustic soda, soda lye
o Preparation: By treating sodium carbonate with lime water.
Na2CO3 + Ca(OH)2 = 2NaOH + CaCO3
o Properties:
 White amorphous pellets
 Slight bitter taste
 Soluble in water, alcohol and glycerin &
 Deliquescent in nature.
o Uses:
 Alkalizing agent
 Disinfectant for animal houses
 For preparation of soap
 Absorb CO2 gas
 Common laboratory reagent.
o Storage: well closed container & protect from moisture & CO2.

8. Chapter 1 Acids, Bases & Buffers Pharmaceutical Chemistry-I Chetan V. Jain (M-Pharma)
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Question Bank
 Explain
o Traditional acid-base theory with examples,
o Discuss Arrhenius acid-base theory with example and list
limitations for it.
or
o Define acid and base as per Arrhenius theory and write
drawbacks of it.
o Bronsted and Lowry acid-base theory with examples,
o Lewis acid-base theory with examples.
 Give Monograph for: all Official Acid as well as base
 Define with examples
o Strong & Weak Acid
o Strong & Weak Base
 Define and give types of Buffer Solutions