Match the starting materials given in Column I with the products formed by these (Column II) in the reaction with HI.
(i —> d), (ii — » e), (iii —> b), (iv — » a)
(i) CH3 – O – CH3 is a symmetrical ether so the products are CH3I and CH2OH.
(ii) In (CH3)2CH – O – CH3 unsymmetrical ether, one alkyl group is primary while another is secondary. So, it follows SN 2mechanism. Thus, the halide ion attacks the smaller alkyl group and the products are
(iii) In this case, one of the alkyl group is tertiary and the other is primary. It follows SN 1 mechanism and halide ion attacks the tertiary alkyl group and the products are (CH3)3 C-I and CH3OH.
(iv) Here, the unsymmetrical ether is alkyl aryl ether. In this ether 0-CH3 bond is weaker than 0-C6H5bond which has partial double bond character due to resonance. So, the halide ion attacks on alkyl group and the products are C6H5-OH and CH3I.
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]
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?
While separating a mixture of ortho and para nitrophenols by steam distillation, name the isomer which will be steam volatile. Give reason.
Give two reactions that show the acidic nature of phenol. Compare its acidity with that of ethanol.
Explain how does the – OH group attached to a carbon of benzene ring activate it towards electrophilic substitution?
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.
Which of the following is an appropriate set of reactants for the preparation of l-methoxy-4- nitrobenzene and why?
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.
Arrange water, ethanol and, phenol in increasing order of acidity and give reason for your answer.
Match the starting materials given in Column I with the products formed by these (Column II) in the reaction with HI.
You are given benzene, cone. H2S04and NaOH. Write the equations for the preparation of phenol using these reagents.
Ethers can be prepared by Williamson's synthesis in which an alkyl halide is reacted with sodium alkoxide. Di-tert-butyl ether cannot be prepared by this method. Explain.
