Acidity of Alcohols, Phenol And Carboxylic Acid Kvcrpfavadi classxii

FACTORS EFFECTING ACIDIC STRENGTH Which factors effect acidic nature Releasing hydrogen ion capacity Bond strength with hydrogen * electronegativity Attachment of groups like CH3 ,C2H5 which createinductive effect Hydrogen bond

Concepts About Acids Arrhenius concept : Acids :- H+ ion donor in aqueous medium Bases :- OH- ion donor in aqueous medium Bronsted & Lowery concept : Acids :- Proton (H+) donor Bases :- Proton (H+) acceptor Lewis concept :- Acids :- Electron pair acceptor Bases :- Electron pair donor

Reactions which shows acidic properties of alcohols, Phenol And Carboxylic Acid

For Alcohols

2R-OH + 2Na 2R-ONa + H2 3R-OH + Al (R-O)3Al + H2

For Phenol

C6H5-OH + Na C6H5-ONa + H2 C6H5-OH + NaOH C6H5-ONa + H2O

For Carboxylic Acids

RCOOH + Na RCOONa + H2 RCOOH + NaOH RCOONa + H2O RCOOH + NaHCO3 RCOONa + CO2 + H2O

Why alcohol, Phenol And Carboxylic Acid shows Acidic Nature?

SUBSTITUENT EFFECT ON ACIDITY OF ALCOHOLS, PHENOL, AND CARBOXYLIC ACID

Substituent On R of Alcohol An electron-withdrawing substituent makes an alcohol more acidic by decreasing the negative charge density on O Alcohols with an electron-donating substituent are less acidic because these substituent concentrate the charge on O

Substituted Phenols Can be more or less acidic than phenol itself An electron-withdrawing substituent makes a phenol more acidic by delocalizing the negative charge Phenols with an electron-donating substituent are less acidic because these substituent concentrate the charge

Q. Arrange the following compounds in decreasing order of their strength Propan-1-ol, 2,4,6-trinitrophenol,3-nitrophenol, 3,5-dinitrophenol, phenol, 4-methyl phenol Ans - 2,4,6-trinitrophenol › 3,5-dinitrophenol › 3-nitrophenol › phenol › 4-methyl phenol › Propan-1-ol

Substituent Effects on Acidity Of Carboxylic Acid pKa = 4.46 pKa = 4.19 pKa = 3.47 pKa = 3.41 pKa = 2.16

Q. Which acid of each pair shown here would you expect to be stronger Q. Which acid of each pair shown here would you expect to be stronger in acidic strength (a) CH3COOH or CH2FCOOH (b) CH2FCH2CH2COOH or CH3CH2CHFCOOH (c) CF3C6H4COOH or CH3C6H4COOH Ans - (a) CH2FCOOH (b) CH3CH2CHFCOOH (c) CF3C6H4COOH

Q. Arrange the following compounds in increasing order of their acidic Q. Arrange the following compounds in increasing order of their acidic property Benzoic acid, 4-nitrobenzoic acid, 3,4-dinitrobenzoic acid, 4- methoxy benzoic acid Ans - 4- methoxy benzoic acid ‹ Benzoic acid ‹ 4-nitrobenzoic acid ‹ 3,4-dinitrobenzoic acid

Comparative Study of Acidic Strength of Alcohol, Phenol And Carboxylic Acid

The greater acidity of carboxylic acids is attributed to The greater acidity of carboxylic acids is attributed to greater stabilization of carboxylate ion by: a. Inductive effect of the C=O group b. Resonance stabilization of the carboxylate ion

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