A. Write the product(s) in each of the following reactions :

B. Write the chemical equations involved in the following reactions :

(i) Reimer-Tiemann reaction

(ii) Friedal-Crafts alkylation of anisole.

OR

A. What happens when:

(i) Phenol reacts with conc. HNO₃

(ii) Salicylic acid reacts with

(iii) Ethyl chloride reacts with NaOCH₃

Write the chemical equations involved in the above reactions.

B. Distinguish between :

(i) Ethanol and Phenol

(ii) Propan-2-ol and 2-methylpropan-2-ol

When ethers are treated with strong acids the C-O bond is broken to give alkyl halides and alcohols.

For the given reaction

(ii)

When tert-butyl alcohol is heated in presence of copper at 573 K it undergoes dehydration or elimination reaction to give 2-methylprop-1-ene.

Rxn:

(iii)

Benzene derivatives are less prone to but it easily undergoes reduction in presence of zinc dust that follows a surface reaction mechanism.

Rxn:

B.

(i) Reamer Tiemann reaction

When phenol is treated with chloroform in presence of a base like NaOH, a dichlorocarbene intermediate is formed that acts as a electrophile and phenol undergoes electrophilic substitution reaction.

Step (i) formation of dichlorocarbene

Step (ii) electrophilic attack of dichlorocarbene

Phenol undergoes electrophilic substitution to give and intermediate which on hydrolysis undergoes oxidation to give salicylaldehyde.

(ii) Friedel crafts alkylation of anisole

When anisole is treated with methyl chloride in presence of anhydrous AlCl₃ it undergoes electrophilic substitution reaction to gives mixture of ortho & para methoxy-toluene as the product.

OR

A.

(i) Phenol is activating and ortho-para directing group for electrophilic substitution. When it is reacted to HNO₃ it undergoes electrophilic substitution multiple times to give a tri derivative of nitrophenol, i.e. 2,4,6-trinitrophenol.

Rxn:

(ii) Salicylic acid undergoes electrophilic substitution when treated with acetic anhydride in presence of acidic medium to give an important compound called aspirin.

Rxn:

(iii) Ethyl chloride when reacts with sodium methoxide it undergoes substitution reaction to give ethyl methyl ether.

Rxn:

B.

The difference between phenol and ethanol is given as follows:

Phenol:

(i) It’s an aromatic structure alcohol with unsaturation.

(ii) The C-O bond is stronger due to positive resonance shown by lone pair on oxygen.

(iii) The increases strength of C-O bond decreases its tendency to readily undergo nucleophilic substitution reaction.

(iv) The distinguishing test of phenol and ethanol is by formation of diazo compound, phenol gives positive diazo coupling test.

(v) Phenol decolourizes bromine solution due to presence of unsaturation.

Ethanol:

(i) It’s a linear unsaturated compound.

(ii) The C-O bond is weaker as compared to phenol

(iii) The positive inductive effect does little to improve C-O bond

(iv) Ethanol does not form a diazo compound so can be distinguished from phenols.

(v) Ethanol gives a positive Iodoform test and forms yellow precipitate where phenol does not react with chloroform.

(vi) FeCl₃ forms a violet complex with ethanol and thus can be detected.

Difference between propan-2-ol and 2-methylpropan-2-ol

Propan-2-ol:

(i) Secondary alcohols prefer S_N² mechanism so the rate of reaction is slower as compared to 3° alcohols.

(ii) When treated with HCl and anhydrous ZnCl₂ the solution becomes turbid but very slowly as compared to 3° carbocation.

(iii) Victor mayer test is shown positive by ethanol as follows:

2-methylpropan-2-ol:

(i) Tertiary alcohols preferentially undergo S_N¹ mechanism and do not depend on attacking reagent.

(ii) When treated with anhydrous ZnCl₂ it undergoes faster reaction and makes the solution turbid as the detection test.

(iii) In case of Victor Mayer’s test, tertiary alcohols do not give any colour change indicating absence of primary of secondary alcohol.