Class 12 Chemistry - Chapter Alcohols Phenols and Ethers NCERT Solutions | How are the following conversions carrie

Explain the following with an example.

(i) Kolbe's reaction.

(ii) Reimer-Tiemann reaction.

(iii) Williamson ether synthesis.

(iv) Unsymmetrical ether.

Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.

Give the equations of reactions for the preparation of phenol from cumene.

Write equations of the following reactions:

(i) Friedel-Crafts reaction-alkylation of anisole.

(ii) Nitration of anisole.

(iii) Bromination of anisole in ethanoic acid medium.

(iv) Friedel-Craft's acetylation of anisole.

Explain why is ortho nitrophenol more acidic than ortho methoxyphenol?

Give two reactions that show the acidic nature of phenol. Compare acidity of phenol with that of ethanol.

Show how are the following alcohols prepared by the reaction of a suitable

Grignard reagent on methanal?

(i)

(ii)

Write the reactions of Williamson synthesis of 2-ethoxy-3-methylpentane starting from ethanol and 3-methylpentan-2-ol.

What is meant by hydroboration-oxidation reaction? Illustrate it with an example.

Give structures of the products you would expect when each of the following alcohol reacts with (a) HCl-ZnCl₂ (b) HBr and (c) SOCl₂.

(i) Butan-1-ol

(ii) 2-Methylbutan-2-ol

For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt (III) chloride

(ii) Potassium tetracyanonickelate(II)

(iii) Tris(ethane-1,2-diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanoferrate(II)

(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N

(ii) Write IUPAC names of all the isomers.

(iii) What type of isomerism is exhibited by different pairs of amines?

Why are solids rigid?

Write any two characteristics of Chemisorption.

Write the structures of the following compounds.

(i) α-Methoxypropionaldehyde

(ii) 3-Hydroxybutanal

(iii) 2-Hydroxycyclopentane carbaldehyde

(iv) 4-Oxopentanal

(v) Di-sec-butyl ketone

(vi) 4-Fluoroacetophenone

Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?

Why are pentahalides more covalent than trihalides?

Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?

Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.

Compare the chemistry of actinoids with that of the lanthanoids with specialreference to:

(i) electronic configuration

(ii) atomic and ionic sizes

(iii) oxidation stateand

(iv) chemical reactivity.

Compare the chemistry of the actinoids with that of lanthanoids with reference to:

(i) electronic configuration

(ii) oxidation states and

(iii) chemical reactivity.

Arrange the following polymers in increasing order of their intermolecular forces.
(i) Nylon 6, 6, Buna-S, Polythene.
(ii) Nylon 6, Neoprene, Polyvinyl chloride.

Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it.

[Cr(NH₃)₆]³⁺ is paramagnetic while [Ni(CN)₄]^2- is diamagnetic.  Explain why?

Account for the following:

(i) pK_b of aniline is more than that of methylamine.

(ii) Ethylamine is soluble in water whereas aniline is not.

(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

(iv) Although amino group is o, p- directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.

(v) Aniline does not undergo Friedel-Crafts reaction.

(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines.

(vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.

Is it true that under certain conditions, Mg can reduce SiO₂ and Si can reduce MgO? What are those conditions?

Explain:   (i) Zone refining    (ii) Column chromatography.

Why is dioxygen a gas but sulphur a solid?

What is meant by 'disproportionation'? Give two examples of disproportionation reaction in aqueous solution.