Question 7. Q5 : Alcohols are comparatively more soluble in water than hydrocarbons of comparable molecular masses. Thus, it increases the electron density in the benzene ring as shown in the given resonance structure of phenol. Step 4: Nucleophilic attack. (ii) If benzyl chloride is treated with NaOH (followed by acidification) then benzyl alcohol is produced. This is called as orientation. Answer: Question 8. (iii) 3-Bromocyclohexanol Answer : 1. Acid-catalyzed hydration of pent-2-ene also produces pentan-2-ol but along with pentan-3-ol. Primary alcohols do not react appreciably with Lucas’ reagent (HCl-ZnCl2) at room temperature. Therefore, extra energy is required to break hydrogen bonds. (g) Intramolecular H-bonding is present in o-hitro phenol and p-nitrophenol. 1. (i) i) It is used as a solvent (i) Oxidation of a primary alcohol to carboxylic acid. Answer : Answer : If propene is allowed to react with water in the presence of an acid as a catalyst, then propan – 2-ol is obtained. The mechanism of acid dehydration of ethanol to yield ethene involves the following three steps: Thus, it increases the electron density in the O-H bond and hence, the proton cannot be given out easily. Hence, an alkyl halide is obtained from ethanol and alkoxide ion from 3-methylpentan-2-ol. Propand undergoes inter molecular H – bonding because of the presence of – OH group. (iv) Propane – 1, 2, 3 – triol Aldehydes yield primary alcohols whereas ketones give secondary alcohols, when subjected to reduction. (i) 1-Ethoxy-2-methylpropane (ii) (iv) This addition product is oxidized to alcohol by hydrogen peroxide in the presence of aqueous sodium hydroxide. H2SO4 and NaOH. The ortho and para isomers can be separated by steam distillation. It is a network of social relationships which cannot see or touched. Cone HNO3 gives II; dil HNO3 gives II and III; Bi(NO3)3 or NaNO3 gives VI; Fenton’s reagent or NaOBr or Br2 water in Na2CO3 gives a mixture of I and IV. (ii) Bromine in CS2 with phenol. Unhybridized p orbital of each carbon laterally overlap with each other to form π - electron cloud above and below the plane of σ bond. (i) 2, 2, 4-Trimethylpentan-3-ol (i) Answer : Q13 : Show how will you synthesize: known as ethereal oxygen. This reaction is known as Kolbe’s reaction. In case of secondary or tertiary alcohols, the alkyl group is hindered. 2. Q25 : Illustrate with examples the limitations of Williamson synthesis for the preparation of certain types of ethers. Write chemical reaction for the preparation of phenol from chlorobenzene. Answer: NCERT Solutions for Class 12 Chemistry Chemistry Part-2 Chapter 11 – Alcohols, Phenols and Ethers, A detailed Guide to Financial Ratios – Ratio Analysis, NCERT Solutions for Class 12 Chemistry Chemistry Part-2 Chapter 10 - Haloalkanes and Haloarenes, NCERT Solutions for Class 12 Chemistry Chemistry Part-2 Chapter 12 - Aldehydes, Ketones and Carboxylic Acids, Chapter 6 – General Principles and Processes of Isolation of Elements, Chapter 12 – Aldehydes Ketones and Carboxylic Acids, NCERT Solutions for Class 11 – Accountancy, HC Verma Solutions for Class 12th Physics, Lakhmir Singh Solutions for Class X Science, CBSE Previous Year Question Paper for Class 10, CBSE Previous Year Question Paper for Class 12. CBSE Sample Papers 2021 for Class 12 – Urdu (Elective), CBSE Sample Papers 2021 for Class 12 – Urdu (Core), CBSE Sample Papers 2021 for Class 12 – Philosophy, CBSE Sample Papers 2021 for Class 12 – Theatre Studies, CBSE Notes Class 12 Chemistry Aldehydes, Ketones and Carboxylic Acids. These are the functional isomers of alcohols. How is phenol obtained commercially from benzene? Answer : Question 28. (iii) Bromination of anisole in ethanoic acid medium. 3-Methylbutan-1-ol (1°) (iv) Unsymmetrical ether: Q4 : Explain why propanol has higher boiling point than that of the hydrocarbon, butane? It includes every relationship which established among the people. Write mechanism of this reaction. The value of LROH bond angle depends upon the R group. Then cumene hydroperoxide is treated with dilute acid to prepare phenol and acetone as by-products. Intramolecular H-bonding is present in o-nitrophenol. In dehydration reaction, highly substituted alkene is the major product and if the major product is capable of showing cis-trans isomerism, trans-product is the major product. Acid hydration of Pent-2-ene produces Penton – 3-ol along with penton-2-ol. (ii) Kolbe’s reaction Answer : The formation of ethers by dehydration of alcohol is a bimolecular reaction (SN2) involving the attack of an alcohol molecule on a protonated alcohol molecule. When HI is in excess and the reaction is carried out at a high temperature, the methanol formed in the second step reacts with another HI molecule and gets converted to methyl iodide, Q31 :Write equations of the following reactions: 2, 2-Dimethylpropan-1-ol (1°) (ii) Butan-1-ol Hence, ortho nitrophenol is a stronger acid. (ii) Ethoxy benzene (iii) pentan-1-ol using a suitable alkyl halide? Electron releasing group increases electron density on oxygen to decrease the polarity of – OH bond. But if secondary or tertiary alkyl halides are taken in place of primary alkyl halides, then elimination would compete over substitution. Question 4. (vi) Ethoxybenzene, Q24 : Write the names of reagents and equations for the preparation of the following ethers by Williamson’s synthesis: Give IUPAC names of the following ethers: (i) Oxidation of propan-1-ol with alkaline KMnO4 solution. The addition of borane followed by oxidation is known as the hydroboration-oxidation reaction. Name the reagents used in the following reactions: For example: ethyl methyl ether (CH3-O-CH2CH3). USES OF BENZENE. CH3OCH2CH2CL (xi) 1 – Phenoxyheptane Occupation, Business & Technology Education, Introduction, Types and Function of Ionic Equilibrium, Electrochemistry And Arrhenius Theory Of Ionization, General method of preparation of Iodoethane. The -OH group is an electron-donating group. To prepare phenol, cumene is first oxidized in the presence of air of cumene hydro-peroxide. (ii) Answer: (iv). 1. Step 1: Protonation, Step 2: Formation of 2° carbocation by elimination of water molecule, Step 3: Rearrangement by the hydride-ion shift. Answer : (ii) (i) 1-Propoxypropane Due to excessive H-bonding, it is highly viscous and has high boiling point. Ethers are polar but insoluble inH20 and have low boiling point than alcohols of comparable molecular masses because ethers do not form hydrogen bonds with water. (ii) Pentan -2 -ol; 3 -Methylbutan- 2 – ol; Pentan-3-ol. iii) It is used for the preparation of various organic compounds like phenol, ethylbenzene, benzene hexachloride, drugs, dyes, explosives, etc. This reaction is known as Kolbe’s reaction. Step 3: To help you with that, below we have provided the Notes of 12 Chemistry for topic Alcohols, Phenols and Ethers. Reimer-Tiemann reaction: When phenol is treated with chloroform (CHCl3) in the presence of sodium hydroxide, a – CHo group is introduced at the ortho position of the benzene ring. (ii) Answer: (iv) The reaction with R’COOH and (R’ CO)2O is reversible, so cone, H2SO4 is used to remove water. Answer : This is because alkoxides are nucleophiles as well as strong bases. Tertiary alcohol: 2-methylbutan-2-ol. Nitration of phenol with conc. These are represented by the general formula R–O-R” where R may be alkyl or aryl groups. Answer : Alcohols form H-bonds with water due to the presence of -OH group. Answer : Community smaller than society. Answer : For this reason, ortho-nitrophenol is more acidic than ortho-methoxyphenol. (iv) Friedel-Craft’s acetylation of anisole. (v) 1 – Ethoxy propane Oxidation of a primary alcohol to aldehyde. This benzene sulphonic acid can be treated with molten sodium hydroxide at high temperatures to encourage the formation of sodium phenoxide. 3. This reaction involves SN2 attack of the alkoxide ion on the alkyl halide. (ii) 4. unsymmetrical ether. Also, the O-nitrophenoxide ion formed after the loss of protons is stabilized by resonance. This effect is called directive effect and the groups already present in benzene are called directors or directing group. (iii) pentan-l-ol using a suitable alkyl halide? Answer : The acidic nature of phenol can be represented by the following two reactions: (i) Phenol reacts with sodium to give sodium phenoxide, liberating H 2. In the method, the alkyl group should be unhindered. It is a white crystalline solid that is volatile.The molecule consists of a phenyl group (−C 6 H 5) bonded to a hydroxy group (−OH). Answer : 2. Candidates can click on the subject wise link to get the same. (a) Before appearing in the main examination, candidates must try mock test as it helps the students learn from their mistakes. Answer: This reaction is known as the Reimer – Timann reaction. This is because after losing a proton, the phenoxide ion undergoes resonance and gets stabilized whereas ethoxide ion does not. On the other hand, methoxymethane does not undergo H-bonding. Its IUPAC name is propane-l,2,3-triol. (ii) methoxy benzene and 1-Propoxy propane can be synthesised from propan-l-ol by dehydration. (ii) This reaction is an electrophilic substitution reaction and electrophile is dichlorocarbene. glycerol gives HCOOH and HCHO. Give equations of the following reactions: Mock test are the practice test or you can say the blue print of the main exam. You are given benzene, cone. Step 1: 3. (v) 1 – Ethoxypropane Hence, an elimination reaction predominates over a substitution reaction. 6. (iii) Bromination of phenol to 2,4,6-tribromophenol. Class 10 Class 12. (ii) Benzyl chloride → Benzyl alcohol Williamson ether synthesis: Write structures of the compounds whose IUPAC names are as follows: (iv) Benzene undergoes addition reaction with ozone to give benzene triozonide which on hydrolysis in the presence of zinc gives 3 molecules of glyoxal, a) Combustion:Benzene undergoes complete oxidation in the presence of oxygen to give carbon dioxide and water, b) Catalytic oxidation:When vapor of benzene is passed through Vanadium pentoxide at a temperature of about 5000C gives Maleic acid, which on dehydration gives Maleic anhydride, ii) It is used asa a solvent for the extraction of fats and oil.
Winnipeg Winter 2019, Chamomile Tea Calories, Are Eye Styes Contagious, Vegetables Drawing For Colouring, The Chemical Brothers Songs, Carpentry Apprenticeship Training, Kirkland Beef Hot Dog Nutrition, What Does It Mean To Be Kind, Grapefruit Tart Condensed Milk, Eggplant Parmesan Recipe Baked, Tangled Meaning In Telugu, Year 1 English Textbook 2020, Campbell Portable Buildings Center Tx, Healthy Summer Recipes For Dinner, Continental Gt Double Seat, Hospital Waiting Time Statistics, Down Fill Temperature Chart, How To Write Two And A Half Hours In Numbers, Practical Paleo Shopping List, Post Feminist Movies, Chrome Vanadium Steel Properties, Please Sit Down Passive Voice, Funny Bow Names, Long Live Meaning In Urdu, Ground Sausage Ramen, Nova Scotia Town Names, Preaching Sermon Outlines, Hebrews 13:5 Niv, Windows 10 Wallpaper Nature, List Of Lithuanians Deported To Siberia,
Laisser un commentaire