This video discusses about arrhenius theory of acid and base, strong acids, weak acids, neutralisation according to arrhenius theory, limitations of arrhenius theory.
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3.3.1 Arrhenius theory of acids and bases
According to Arrhenius concept (1887)
Acid :- Acid is a substance which contains hydrogen and
gives rise to H+ ions in aqueous solution
HCl(aq)→H+(aq) +CL- (aq)
Strong acid
CH3COOH(aq) CH3COO-(aq) + H+ (aq)
Weak acid
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Acidic properties are due to
presence of H+ ions
Arrhenius described H+ ions in
water as bare ion.
But H+ ion has very small size and
high charge density.
Therefore it readily bind to water
molecule to form hydronium ion
H3O+
But for shake of convenience we
write it as H+
3.3.1 Arrhenius theory of acids and bases
H+ +H2O→ H3O+
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3.3.1 Arrhenius theory of acids and bases
Base :-
Base is substance which contains OH group and produces
hydroxide ions i.e. OH- ions in aqueous solution.
E.g.
NaOH(aq)→Na+(aq) +OH- (aq)
Strong base
NH4OH(aq) NH4
+(aq) +OH- (aq)
Weak base
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According to Arrhenius theory
Neutralization reaction is defined as the reaction in which H+ ion
from acid combines with OH- ion from base to form undissociated
water molecule.
E.g.
HCl(aq) + NaOH(aq) →NaCl (aq) +H2O(l)
H+ (aq) +Cl(aq) + Na+ (aq) + OH-(aq) → Na+(aq) +CL- (aq) + H2O(l)
H+ (aq) + OH-(aq) → H2O(l)
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Limitations of Arrhenius theory:-
1)Arrhenius theory is applicable only to aqueous
solutions.
2) Arrhenius theory does not account for the basicity of
NH3,Na2CO3 which do not have OH- group.