EQUILIBRIUMEQUILIBRIUM PART- II

ACIDS D fi tiDefinationBasicity of an acidCl ifi ti f idClassification of acids

BASESDefinationDefinationAcidity of baseClassification of basesClassification of bases

ALKALINEUTRALISATIONNEUTRALISATIONSALTS

ACIDS USED IN DAILY LIFEACIDS USED IN DAILY LIFE.

Milk contains lactic acid.

Carbonic acid is responsible for theCarbonic acid is responsible for the fizz in soft drinks.

A bi id i th h i l fA bi id i th h i l fAscorbic acid is the chemical name ofAscorbic acid is the chemical name ofvitamin vitamin ––C.C.

Vinegar used in cooking containsVinegar used in cooking containsapproximately 4 % acetic acid.approximately 4 % acetic acid.

Sulphuric acid is used in the manufactureSulphuric acid is used in the manufactureSulphuric acid is used in the manufactureSulphuric acid is used in the manufactureof car batteries.of car batteries.

T il t lToilet cleaner

What is an acid?What is an acid?

ACIDSAn acid is a substance which contains one or more replaceable hydrogen atoms andor more replaceable hydrogen atoms and dissociates in solution giving hydrogen ions( H+ )ions( H+ ).

Ex : 2 HCl + 2 Na→ 2NaCl + H22

one molecule of HCl contains one replaceable h drogen atomreplaceable hydrogen atom.

HCl (aq) → H+ + Cl-(aq)

H SO Z Z SO HH2SO4 (aq) + Zn → ZnSO4 + H2

one molecule of H2SO4 contains two o e o ecu e o 2SO4 co ta s t oreplaceable hydrogen atoms.

H2SO4 (aq) → 2 H+ + SO42-

2 4 (aq) 4

HNO H+ + NOHNO3 (aq) → H+ + NO3–

CH3COOH +NaHCO3 → CH COON CO H OCH3COONa + CO2 + H2O

one molecule of CH3COOH contains one 3replaceable hydrogen atom.

CH3COOH (aq) → H+ + CH3COO –3 (aq) 3

Mineral acids and organic acids.g

A mineral acid (or inorganic acid) is an acid derived from one or more inorganic compounds. g p

All mineral acids form hydrogen ions when dissolved in water.Ex: HCl , HNO3 H2SO4 etc

Organic compounds having acidicproperty are organic acids.p p y g

Ex: Carboxylic acidsEx: Carboxylic acidsHCOOHCH COOHCH3COOHC6H5COOH

BASICITY OF AN ACID

It is the number of replaceable hydrogen atoms present in a molecule of an acid.

CLASSIFICATION OF ACIDS :CLASSIFICATION OF ACIDS :

D di th b i it f th idDepending on the basicity of the acids, they are classified as: y

Monobasic acidDib i idDibasic acid Tribasic acid etc.

MONOBASIC ACIDMONOBASIC ACID

Monobasic acid contains one replaceableMonobasic acid contains one replaceable hydrogen atom in a molecule.EEx : Hydrochloric acid - HClyNitric acid - HNO3

For organic acids basicity is the number of-COOH groups present in the molecule-COOH groups present in the molecule.Ex :

HCOOHCH COOHCH3COOHC6H5COOH

DIBASIC ACIDDibasic acid contains two replaceable

DIBASIC ACIDDibasic acid contains two replaceablehydrogen atoms in a molecule.Ex :Ex : Sulphuric acid - H2SO4 Oxalic acid - C2 H2O4

( HOOC –COOH)( )

TRIBASIC ACID

A tribasic acid contains three replaceable hydrogen atoms in a molecule.Ex :Ex : Orthophosphoric acid - H3PO4

Almost all inorganic acids are soluble in waterwater.For volumetric analysis, solution of acids having different concentrations are prepared. p pConcentration of acids are expressed in normality or molaritynormality or molarity.

Why SO3 , BF3 etc are acids?

BASES USED IN DAILY LIFE.

Antacids help to neutralize the acidity in Antacids help to neutralize the acidity in th t hth t hthe stomach. the stomach. They mainly contain two bases:They mainly contain two bases:

Mg(OH)Mg(OH)22&&&&

Al(OH)Al(OH)33

Potassium hydroxide is used in the manufacture of alkaline batteriesmanufacture of alkaline batteries.

Ammonia is a basic gas which isAmmonia is a basic gas which is used in the manufacture offertilizers such as :ureaureaammonium nitrate ammonium phosphate.

What is a base?What is a base?

BASESA base is a substance which dissociates in solution giving hydroxyl ( OH - ) ionsin solution giving hydroxyl ( OH ) ions.

Th id d h d id f t lTh id d h d id f t lThe oxides and hydroxides of metals The oxides and hydroxides of metals are bases or basic in nature.are bases or basic in nature.

Ex : Sodium hydroxide ( NaOH )is a Ex : Sodium hydroxide ( NaOH )is a base.base.NaOH dissociates in solutionNaOH dissociates in solutionNaOH dissociates in solution NaOH dissociates in solution NaOH → NaNaOH → Na++ + OH + OH ––

Calcium hydroxide Ca(OH)2 is a base Ca(OH) dissociates in solutionCa(OH)2 dissociates in solution. Ca(OH)2 → Ca2+ + 2 OH –

Aluminium hydroxide Al(OH) is a baseAluminium hydroxide Al(OH)3 is a base Al(OH)3 dissociates in solution. Al(OH)3 → Al3+ + 3 OH –

ACIDITY OF BASEACIDITY OF BASE

It is the number of molecules of monobasic acid required to neutralizemonobasic acid required to neutralize one molecule of a base.

Ex : NaOH + HCl → NaCl + H2O

Acidity of NaOH is oneAcidity of NaOH is oneor

NaOH is monoacidic base.

Ca(OH)2 + 2HCl → CaCl2 + 2H2O2 2 2

Acidity of Ca(OH) is twoAcidity of Ca(OH)2 is two or

Ca(OH)2 is diacidic base.

Al(OH)3 + 3HCl → AlCl3 + 3H2O

Acidity of Al(OH)3 is three or

Al(OH) is triacidic baseAl(OH)3 is triacidic base.

ACIDITY OF BASEACIDITY OF BASE

Acidity of hydroxide is the number y yof hydroxyl (OH) groups present in a molecule of itmolecule of it.

Base AcidityNaOH 1

Ca(OH) 2Ca(OH)2 2Al(OH)3 3

H t d t t th id & b ?How to detect the acids & bases?

Acids turns blue litmus to redAcids turns blue litmus to red.Bases turns red litmus to blue.

Why CaO ,MgO are bases?Why CaO ,MgO are bases?

ALKALI

The bases which are readily The bases which are readily soluble in water are called alkalisoluble in water are called alkalisoluble in water are called alkali.soluble in water are called alkali.

Oxides and hydroxides of “group - 1 ’’metals of long form of periodic table aremetals of long form of periodic table are readily soluble in water. They are called alkaliesalkalies.

These metals are called alkali metals.

Ex:Ex: NaOH is a base and also an alkali. KOH is a base and also an alkali.Mg(OH) Ca(OH) are bases only but notMg(OH)2, Ca(OH)2 are bases only but not alkalies.

All the alkalies are bases but all the basesAll the alkalies are bases but all the bases are not alkalies.

NEUTRALISATION

The reaction between an

NEUTRALISATION

The reaction between an acid and a base in dilute aqueous solution is calledaqueous solution is called neutralisation reaction.

Ex: HCl + NaOH → NaCl + H OEx: HCl(aq)+ NaOH (aq)→ NaCl(aq) + H2O

HH SOSO 2N OH2N OH NN SOSO 2H2H OOHH22SOSO4(aq)4(aq)+ 2NaOH + 2NaOH (aq)(aq)→Na→Na22SOSO4 (aq)4 (aq) + 2H+ 2H22OO

CHCH33COOH +NaOH → CHCOOH +NaOH → CH33COONa + HCOONa + H22OO33 33 22

What are salts?What are salts?

SALTThe Chemical substance obtained as a result of neutralisation reaction betweenresult of neutralisation reaction between an acid and a base is called salt.Ex: HCl(aq)+ NaOH(aq) →NaCl(aq)+ H2O

H2SO4 (aq)+ 2NaOH(aq)→Na2SO4(aq)+2H2O

HNO3 (aq) + NaOH(aq) → NaNO3(aq) +H2O( q) ( q) ( q)

HCl + KOH KCl +H OHCl(aq) + KOH(aq) → KCl(aq) +H2O

HNO3 (aq) + KOH(aq) → KNO3(aq) +H2O