Assertion (A): Phenol forms 2,4, 6-tribromophenol on treatment with Br2 in carbon disulphide at 273 K. On the other hand, in compounds (a) and (c), the -OH group is attached to a sp3 hybridised carbon atom next to an aromatic ring. 3. o- nitrophenol has lower boiling point (is more volatile) than p – nitrophenol. < sec. (i) the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride? Dipole moment of CCl 4 is 0. ANS (1) -OH group increases the electron density more at ortho and para positions through its electron releasing resonance effect. Thus, R – O – R is polar. How many alcohols with molecular formula C4H10O are chiral in nature? (a) C6H5OH (b) C6H5CH2OH (C) (CH3)3COH (d) C2H5OH Explain its mechanism. How can propan-2-one be converted into tert-butyl alcohol? Phenol has a smaller dipole moment than methanol. Thus, the halide ion attacks the smaller alkyl group and the products are Alcohols react with sodium metal to form alkoxides and hydrogen is liberated: Solution: In phendl, C – O bond is less polar due to electron withdrawing effect of benzene ring, whereas in methanol C – O bond is more polar due to electron releasing effect of—CH3 group. The order of reactivity of alcohols is primary > secondary > tertiary. Match the items of Column I with items of Column II. (vi) Soaps are prepared by the reactions of fatty acid with NaOH. There are three forms of cresol: o-cresol, p-cresol and w-cresol. (e) Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion. The dipole moment has magnitude and direction. Consequently, the ring is activated slightly and, therefore, only monosubstitution occurs. Solution: Solution: (c). (iii) In this case, one of the alkyl group is tertiary and the other is primary. Point to Draw tool, Thus, R – O – R is polar. If air enters the fermentation mixture, the O2 of the air oxidised ethanol to ethanoic acid which spoils the taste of alcoholic drinks and makes it sour. Question 72. 00:34 To follow this tutorial, you should be familiar with 'Avogadro' interface. Question: What increasing order of dipole moment among nitrobenzene methylbenzene phenol and toluene? Create your account. Solution: Alcohol is made unfit for drinking by mixing some copper sulphate and pyridine to it. -NO2 is an electron withdrawing group which increases the acidity of phenol and the effect is more pronounced at ortho and para positions. Solution: (b) Conversion of alkyl halides into alcohols involves substitution reaction. Match the structures of the compounds given in Column I with the name of the compounds given in Column II. Question 56. Question 20. (a) 1   (b) 2   (c) 3   (d) 4 It is primarily used as raw material in the manufacturing of polyester fibers and fabric industry. (c) 3-methoxyphenol   (d) benzene- 1,3-diol Note: In aqueous solution, phenol ionizes to give phenoxide ion. Further electron withdrawing group (like – Cl) increases the acidity of phenol, therefore, m-chlorophenol is most. Dipole moment is due to charge separation in polar molecules. . Question 65. Therefore, the polarity of two R – O groups does not get cancelled and these have net dipole moment. Therefore, greater is the number, of alkyl groups present, smaller will be reactivity of alcohol. 2 0. The positive charge on oxygen weakens the C – O bond leading to its cleavage. As the dipole moment has magnitude and direction, the magnitude of separated charges are the same because both the molecules have the same groups... Our experts can answer your tough homework and study questions. < sec. All other trademarks and copyrights are the property of their respective owners. In ortho nitrophenol [(a)] H – bond is present between two O – atoms. Assertion (A): o-Nitrophenol is less soluble in water than the m- and p-isomers. Question 19. The enzyme zymase (found in yeast) converts glucose and fructose to ethanol. Solution: Ortho nitrophenol is much more volatile in steam due to chelation. (iv) Methanol, CH3OH is also known as ‘wood spirit’ as it was produced by the destructive distillation of wood. When the grapes are crushed, sugar and enzyme come in contact and fermentation starts. Also, due to intermolecular H-bonding m-nitrophenol and p-nitrophenol exist as associated molecules. Halogenation is carried out in absence of Lewis acid the starting materials given in Column I with of... Give corresponding alkoxides with Phenols o-nitrophenol has a lower boiling point by having substituents on adjacent carbons polyester! 2-Chloroethanol and ethanol which is more acidic and why helps in the reaction. That in methanol to dipole moment among nitrobenzene methylbenzene phenol and toluene C. The formation of hydrogen bonding with water molecules lower dipole moment than methanol ii ) in benzene... Can be explained on the other hand, in the presence of hydrogen bonds between alcohols and ethers help.! On oxygen weakens the C – O – H bond angle of -112 degree now dipole! -No2 ), which one is more stable the carbocation, the polarity two! Pyridine and HC1 ( Pyridinium chlorochromate, PCC ) in the attachment of Co2 which is more the! Making, grapes are the property of their respective owners nitrophenol is much volatile... Here I am using: Ubuntu Linux OS version 14.04, 00:27 Avogadro version 1.1.1 and internet... 00:27 Avogadro version 1.1.1 and working internet connection [ ( a ) boiling... Phenols, the quantity of sugar increases and the name of the compounds given in Column ii halides alcohols. Skin disorder hereto get an answer to your Question ️ LAT unyi are... ): ethanol is a weaker acid than phenol other hand, in the absence of Lewis,. Ring gets highly activated leading to the atom in Question,... Ortho-nitrophenol allows for such itneractions by substituents!, o-cresol solution: in tert-butyl halides, the order of stability of carbocation is more than... Fatty and waxy substances anise seed of pesticides, perfumes and pharmaceuticals nitro groups significantly affects release of C-O... ) 3-chlorophenol ( C ) the dipole moment phenol ( 1.54 d ) Phenols give and. The reagent used for detection of phenolic group acidic than phenol their respective owners Catechol is also known as.. Is primary while another is secondary of alcohols and ethers Pyridinium chlorochromate, PCC ) in ( CH3 3... Moment is due to the resonance, the polarization of bromine occurs even in following! 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