3 Acidity of Phenol. As of this date, Scribd will manage your SlideShare account and any content you may have on SlideShare, and Scribd's General Terms of Use and Privacy Policy will apply. 4 ��ࡱ� > �� ���� y � b � r � ` � � � � � � } y � ~ � If you continue browsing the site, you agree to the use of cookies on this website. You can change your ad preferences anytime. The concepts used … Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by –OH group. Acidity of phenol. If you continue browsing the site, you agree to the use of cookies on this website. 9 Hydrogen Bonding in Phenols 10 Physical Properties (Table 24.1) Compared to compounds of similar size The phenols are acidic in nature and stronger acids than alcohols. REACTIONS OF PHENOLSREACTIONS OF PHENOLS Chemically, phenols are weakly acidic compounds.Chemically, phenols are weakly acidic compounds. ����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� Phenols are acidic due the formation of more stable phenoxide ions in aqueous solution. An alcohol contains one or more hydroxyl (OH) group(s) directly attached to carbon atom(s), of an aliphatic system (CH3OH) while a phenol contains –OH group(s) directly attached to carbon atom(s) … ����8 A weak acid (pH 5 6) Dissolves in NaOH(aq) to give sodium phenoxide salt. Weaker acid than carboxylic acids but stronger acid than water and ethanol. Phenol is more acidic than alcohols by considering the resonance effect. Phenols are more acidic than alcohols but less acidic that carboxylic acid. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. The top layer is a solution of phenol in water, and the bottom one a solution of water in phenol. If you wish to opt out, please close your SlideShare account. Litmus paper is blue at pH 8 and red at pH 5. X= -H -Cl -Br -NO2 pKa ~ 10 9.4 9.3 7.2 The influence of a substituent on phenol acidity is also dependent on its position relative to the -OH pKa X= -Cl 9.4 9.1 -NO2 7.2 8.4 -OCH3 10.2 9.6 -CH3 10.3 10.1 * The effect of multiple substituents on phenol acidity is additive. 4 Give the IUPAC name of the following […] Alcohols,phenols, ethers 1. The acidity of a carboxylic acid is higher than alcohols and even phenols. A weak acid (pH 5 6) Dissolves in NaOH(aq) to give sodium phenoxide salt. DEPT OF CHEMISTRY 2. Phenol itself is the simplest of these with nothing else attached to the ring apart from the -OH group. Give the IUPAC name of the following compound : (Delhi 2009) Answer: IUPAC name : 2-Bromo-3-methyl-but-2-ene-1-ol Question 2. Important Questions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ethers Class 12 Important Questions Alcohols, Phenols and Ethers Class 12 Important Questions Very Short Answer Type Question 1. 22.6: Sources of Phenols. This is due to the fact that the sp 2 hybridised carbon of phenol to which −OH is attached, is highly electronegative which causes a decrease in electron density on oxygen. See our User Agreement and Privacy Policy. Phenols are aromatic compounds containing atleast one hydroxyl group attached to benzene ring. No public clipboards found for this slide. Phenol, the cresols (methylphenols), and other simple alkylated phenols can be obtained from the distillation of coal tar or crude petroleum.. Nomenclature of phenols. # $ % &. Many phenolic compounds were discovered and used long before chemists were able to determine their structures. Most other phenols are insoluble in water. This is indicated in the order of acidity constants: Phenols are acidic due to the formation of stable phenoxide ion in aqueous solution. PHENOLS R-OH + H2O alcohol OH R-O- + H3O+ Ka = ~ 10-16 to 10-18 alkoxide ion H2O phenol H 2 O + H2 O O- H3O + Ka = 1.2 x 10-10 phenoxide ion HO- + H3O+ hydroxide ion Ka = 1.8 x 10-16 31. Alcohols are considered neutral with pKa values similar to water (pKa = 14). most of the more compl ex plan t poly ph enol s cont ain these two simple phenol s as a part s of th eir st ruct ur es, ca tech ol and phlor oglu ci nol are unco mmon in plant tissue s.