Why is the C – O – H bond angle‘in alcohols slightly less than the tetrahedral angle whereas the C – O – C bond angle in ether is slightly greater?
The C – O – H bond angle in alcohols is slightly less than the tetrahedral angle (109.5 °) because of larger repulsions between the lone pairs of electrons. For example in methanol C – O – H bond angle is 108.9 °.
In ethers, the C – O – C bond angle is slightly greater than tetrahedral angle. For example in dimethyl ether C – O – C bond angle is 111.7 °. The larger bond angle in ethers may be because of greater repulsions between bulkier alkyl groups as compared to one H in alcohols.
Assertion (A): Boiling points of alcohols and ethers are high.
Reason (R): They can form intermolecular hydrogen bonding.
Name the enzymes and write the reactions involved in the preparation of ethanol from sucrose by fermentation.
Explain why is OH group in phenols more strongly held as compared to OH group in alcohols.
Assertion (A): Bond angle in ethers is slightly less than the tetrahedral angle. Reason (R): There is a repulsion between the two bulky (-R) groups.
Assertion (A): Ethanol is a weaker acid than phenol.
Reason (R): Sodium ethoxide may be prepared by the reaction of ethanol with aqueous NaOH.
Explain a process in which a biocatalyst is used in industrial preparation of a compound known to you.
Explain why alcohols and ethers of comparable molecular mass have different boiling points.
When phenol is treated with bromine water, white precipitate is obtained. Give the structure and the name of the compound formed.
Why is the reactivity of all three classes of alcohols with cone. HCl and ZnCl2 (Lucas reagent) different?
Write structures of the compounds whose IUPAC names are as follows:
(i)2-Methylbutan-2-ol
(ii)l-Phcnylpropan-2-ol
(iii)3,5-DimethyIhexane-l,3,5-triol
(iv)2,3-Dicthylphenol
(v)1-Ethoxypropane
(vi)2-Ethoxy-3-methylpentane
(vii) Cyclohexylmethanol
(viii) 3-Cyclohexylpcntan-3-ol
(ix)Cyclopcnt-3-en-l-ol
(x)4-ChIoro-3-ethylbutan-l-ol
Assertion (A): IUPAC name of the compound
Reason (R): In IUPAC nomenclature, ether is regarded as hydrocarbon derivative in which a hydrogen atom is replaced by -OR or -OAr group [where R = alkyl group and Ar = aryl group]
While separating a mixture of ortho and para nitrophenols by steam distillation, name the isomer which will be steam volatile. Give reason.
Explain how does the – OH group attached to a carbon of benzene ring activate it towards electrophilic substitution?
In Kolbe's reaction, instead of phenol, phenoxide ion is treated with carbon dioxide. Why?
Why is the C – O – H bond angle‘in alcohols slightly less than the tetrahedral angle whereas the C – O – C bond angle in ether is slightly greater?
Assertion (A): p-Nitrophcnol is more acidic than phenol.
Reason (R): Nitro group helps in the stabilization of the phenoxide ion by dispersal of negative charge due to resonance.
Give two reactions that show the acidic nature of phenol. Compare its acidity with that of ethanol.
Phenol can be distinguished from ethanol by the reactions with ………….
(a) Br2/water (b) Na
(c) Neutral FeCl3 (d) All of these
Write the structures of the isomers of alcohols with molecular formula C4H10O. Which one of these isomers exhibits optical activity?
Preparation of alcohols from alkenes involves the electrophilic attack on alkene carbon atom. Explain its mechanism.
Match the starting materials given in Column I with the products formed by these (Column II) in the reaction with HI.
Which of the following is an appropriate set of reactants for the preparation of l-methoxy-4- nitrobenzene and why?
Arrange water, ethanol and, phenol in increasing order of acidity and give reason for your answer.
Give structures of the products you would expect when each of the following alcohol reacts with (a)HCl-ZnCl2 (b)HBrand (c) SOCl2
(i)Butan-1-ol
(ii)2-Methylbutan-2-ol
(i) Draw the structures of all isomeric alcohols of molecular formula C5HI20 and give their IUPAC names.
(ii) Classify the isomers of alcohols in question (i)as primary, secondary and tertiary alcohols.
You are given benzene, cone. H2S04and NaOH. Write the equations for the preparation of phenol using these reagents.
How are the following conversions carried out?
(i) Propene —> Propan -2-ol
(ii) Benzyl chloride —> Benzyl alcohol
(iii) Ethyl magnesium chloride —> Propan-l-ol
(iv) Methyl magnesium bromide —> 2-Methylpropan-2-ol
