Class 12 Chemistry - Chapter Alcohols Phenols and Ethers NCERT Solutions | Which of the following is an appropriate

Explain the following with an example.

(i) Kolbe's reaction.

(ii) Reimer-Tiemann reaction.

(iii) Williamson ether synthesis.

(iv) Unsymmetrical ether.

How are the following conversions carried out?

(i) Propene → Propan-2-ol

(ii) Benzyl chloride → Benzyl alcohol

(iii) Ethyl magnesium chloride → Propan-1-ol.

(iv) Methyl magnesium bromide → 2-Methylpropan-2-ol.

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.

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.

Explain why inspite of nearly the same electronegativity, oxygen forms hydrogen bonding while chlorine does not.

Explain why fluorine forms only one oxoacid, HOF.

Why are halogens strong oxidising agents?

How is SO₂ an air pollutant?

Benzene and toluene form ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at 300 K are 50.71 mm Hg and 32.06 mm Hg respectively. Calculate the mole fraction of benzene in vapour phase if 80 g of benzene is mixed with 100 g of toluene.

Describe the manufacture of H₂SO₄ by contact process?

Which aerosols deplete ozone?

Knowing the electron gain enthalpy values for O → O^- and O → O^2- as -141 and 702 kJ mol^-1 respectively, how can you account for the formation of a large number of oxides having O^2- species and not O^-? (Hint: Consider lattice energy factor in the formation of compounds).

Why is dioxygen a gas but sulphur a solid?

Determine the osmotic pressure of a solution prepared by dissolving 25 mg of K₂SO₄ in 2 liter of water at 25° C, assuming that it is completely dissociated.