Class 12 Chemistry - Chapter Alcohols Phenols and Ethers NCERT Solutions | Preparation of ethers by acid dehydratio

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?

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

Grignard reagent on methanal?

(i)

(ii)

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

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.

Why is it essential to wash the precipitate with water before estimating it quantitatively?

Can you store copper sulphate solutions in a zinc pot?

Classify the following as amorphous or crystalline solids:
Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Gold (atomic radius = 0.144 nm) crystallises in a face-centred unit cell. What is the length of a side of the cell?

Action of soap is due to emulsification and micelle formation. Comment.

Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.

What is the covalence of nitrogen in N₂O₅?

For M²⁺/M and M³⁺/M²⁺ systems, the E^⊖  values for some metals are as follows:

Cr²⁺/Cr -0.9V

Cr³/Cr²⁺ -0.4 V

Mn²⁺/Mn -1.2V

Mn³⁺/Mn²⁺ +1.5 V

Fe²⁺/Fe -0.4V

Fe³⁺/Fe²⁺ +0.8 V

Use this data to comment upon:

(i) The stability of Fe³⁺in acid solution as compared to that of Cr³⁺or Mn³⁺ and

(ii) The ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.

Write the important structural and functional differences between DNA and RNA.

Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.