Ortho and para nitrophenols are more acidic than phenol

The resonance structure of o- and p nitrophenoxide ions and phenoxide ion are given below: It is evident from the above structures that due to -R-effect of the − N O 2 group, o- and p-nitrophenoxide ions are more stable (because of additional resonance structures, III and IX enclosed in boxes) than phenoxide ion. as a result, o- and p-nitrophenols are more acidic than phenol.

Chemical compound with the 6H 4NO 2. Three • o-Nitrophenol (2-nitrophenol; OH and NO 2 groups are neighboring, a yellow solid. • m-Nitrophenol (3-nitrophenol, CAS number: 554-84-7), a yellow solid (m.p. 97 °C) and precursor to the drug • p-Nitrophenol, yellow solid is a precursor to the The mononitrated phenols are often Di- and trinitrophenols [ ]

Acid is any chemical that produces hydrogen ions when dissolved in water. When phenol is mixed with water, it disintegrates into two ions: hydrogen and phenoxide. Resonance helps to keep the phenoxide ion stable. As a result, phenol is acidic. Explanation of the Acidic Nature of Phenol: Phenols are acidic because they produce phenoxides and lose hydrogen ions. The hydroxyl group in the benzoyl group has an electron-withdrawing unit that is directly connected to carbon. The electronegativity of hydroxyl groups is higher than that of benzene rings. So- • Around the hydroxyl group, the oxygen atom’s electronegativity increases, and its electron density falls. • Phenoxides are produced as a result. The benzene ring’s resonance stabilises the phenoxide ion produced by the delocalisation of the negative charge. • When resolving charge separation during resonance, the phenoxide ion is more stable than the phenol ion. Because of the phenoxide ion and the resonance of the negative charge, electron-withdrawing groups increase the acidity of substituted phenols. The phenoxide ion is generated when resolving charge separation during resonance; the stable solution determines charge separation during resonance. The acidity of a chemical increases dramatically when ortho- and para-linked phenolic groups are present. The Acidic Character of Phenol: The resonance structures of phenoxide ions explain the delocalisation of the negative charge. When an electron-withdrawing group is present in...

We know that the nitrophenols are more acidic than phenol. Their acidic strength can be compared in terms of the relative stabilities of the corresponding phenoxide ions based on resonance. For example, (i) Phenoxide ion : (ii) o-Nitrophenoxide ion : (iii) p-Nitrophenoxide ion : In case of nitrosubstituted phenoxides, the contributing structures that are enclosed in boxes have negative charge on the carbon atom to which the electron withdrawing nitro group is attached. They therefore, contribute more towards the acidic character than the rest of the contributing structures. Consequently, both ortho and para nitrophenol are stronger acids than phenol.

Chemical properties of any organic compound largely depends on the functional group attached to it. The hydroxyl group (-OH) determines most of the chemical properties of alcohols and phenols. The following types of reactions are seen in -OH derivatives : • Reactions involving the cleavage of the oxygen-hydrogen bond (R−O ...H). • Reactions involving the cleavage of the carbon-hydroxyl bond (C ...OH). • Dehydration and oxidation reactions. • Electrophilic substitution reactions in phenols. The cleavage of O−H bond Both alcohols and phenols readily release proton (the H + ion attached to the oxygen atom). Acidic character Take a look at the reactions below : Alcohols are weaker acids than water Reason : Electron attracting groups ( Phenols ,however, are stronger acids than water because they form phenoxide ion on losing a proton which is resonance stabilized. Comparison of acidity of primary, secondary and tertiary alcohols : Alkyl groups being electron donating in nature increase the +I-effect. Hence, +I-effect in alcohols follows the order : Although both phenol and phenoxide ion are stabilized by resonance, phenoxide ion only carries a negative charge whereas phenol involves a separation of negative and positive charge. Since resonance structures that involve separation of negative and positive charge are less stable (discussed in Lets take the case of alcohols Alcohols release protons to form alkoxide ions and neither the alcohol molecule nor the alkoxide ion exhibits r...

CH 3 ​ CH 2 ​ CH 2 ​ CH 2 ​ ⟷ CH 3 ​ CH 2 ​ CHCH 3 ​ ⟶ detry ​ CH 3 ​ − CH = CH − CH 3 ​ HSO 4 − ​ ​ 10.8. Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the corresponding phenoxide ions. Ans. − NO 2 ​ group is electron withdrawing ( − R effect), it increases the stability of o - and p-nitropher ion) as compared to phenoxide ion. Resonating structures of ortho-nitrophenoxide ion. Views: 5,810 reported by H.C. ​ to give trialkyl boranes as addition product. This is oxidised to ​ (ii) By hydroboration-oxidation: Diborane ( BH 3 ​ ) 2 ​ reacts with alkenes his studies on boron alcohol by hydrogen peroxide in the presence of aqueous sodium containing organic compounds, Brown shared the 1979 Nobel prize in Chemistry with G. Wittig. ( CH 3 ​ − CH 2 ​ − CH 2 ​ ) 3 ​ B ⟵ CH 3 ​ − CH = CH 2 ​ ​ ( ↓ CH 3 ​ − CH 2 ​ CH 2 ​ ( CH 3 ​ − CH 2 ​ − CH 2 ​ ) 2 ​ BH ​ H 2 ​ O ↓ 3 H 2 ​ O 2 ​ , O H 3 CH 3 ​ − CH 2 ​ − CH 2 ​ − OH + B ( OH ) 3 ​ ​ Propan-1-ol The addition of borane to the double bond takes place in such a manner that the boron atom gets attached to the s p 2 carbon carrying greater number of hydrogen atoms. The alcohol so formed looks as if it has been formed by the addition of water to the alkene in a way opposite to the Markovnikov's rule. In this reaction, alcohol is obtained in excellent yield. 2. From carbonyl compounds (i) By reduction of aldehydes and ketones: Aldehydes and ketones Views: 5,061 > A > B > C (4) D > C > B > A (3)...

The electron withdrawing groups are more effective in increasing the acidic strength at the para-position relative to the ortho position because of greater dispersal of charge on oxygen atom. Resonance structure of phenoxide ion: Resonance structure of paranitrophenol : Resonance structures of ortho nitro phenol: Thus, presence of nitro group at ortho and para position incerease the acidic character Categories • • (31.9k) • (8.8k) • (764k) • (248k) • (2.9k) • (5.2k) • (664) • (121k) • (72.1k) • (3.8k) • (19.6k) • (1.4k) • (14.2k) • (12.5k) • (9.3k) • (7.7k) • (3.9k) • (6.7k) • (63.8k) • (26.6k) • (23.7k) • (14.6k) • (25.7k) • (530) • (84) • (765) • (49.1k) • (63.8k) • (1.8k) • (59.3k) • (24.5k)

Resonating structures of o-nitrophenoxide ions that are formed by the loss of proton from o-nitrophenol are as follows: Resonating structures of p-nitrophenoxide ions that are formed by the loss of proton from p-nitrophenol are as follows: Resonating structures of phenoxide ions that are formed by the loss of proton from phenol are as follows: It is clearly evident from the above structures that due to —R-effect of— NO _ group, o-and p-nitrophenoxide ions are more stable than phenoxide ions. Consequently, o- and p-nnitrophenols are more acidic than phenols.