(CH₃)₂C = C (CH₃)₂

(i) Phenol are only sparingly soluble in water. Actually they form only negligible hydrogen bonding with water since the size of the phenyl group is large and it almost masks the polar character of -OH group. So, phenol has a smaller dipole moment.

(ii) But methanol is soluble in soluble in water due to the formation of hydrogen bonding with water and it results in higher dipole moment. In henol, there is +ve charge on oxygen, therefore it does not undergo protonation easily.

When glycerol is heated with dehydrating agents such as Con H₂SO, KHSO₄ etc .... , it undergoes dehydration to form acrolein.

Tertiary alcohols do not undergo oxidation reaction under normal conditions, but at elevated temperature under strong oxidizing, agent cleavage of C-C-bond takes place to give a mixture of carboxylic acid.

Yes, we can use nucleophiles such as NH₃, CH₃O^- for the nucleophilic substitution of alcohol.
Example
\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}+\mathrm{NH}_{3} \rightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}+\mathrm{H}_{2} \mathrm{O} \)
\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}+\mathrm{CH}_{2} \mathrm{~N}_{2} \rightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OCH}_{3}+\mathrm{N}_{2}\)

In phenol the electron density is increased in the benzene ring and hence the benzene ring is activated towards electrophilic substitution reaction and -OH group does not undergo substitution reaction like alcohol.

Ethers having same molecular formula, but alkyl groups attached to the oxygen atom are different. This phenomenon is known as metamerism.
Metamers of 2- methoxy propane
\(\mathrm{C}_{2} \mathrm{H}_{5}-\mathrm{O}-\mathrm{C}_{2} \mathrm{H}_{5}-\) diethyl ether 
\(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\) methyl n-propyl ether

Saytzeff's rule: During intramolecular dehydration, if there is a possibility to form a carbon-carbon double bond at different locations, the preferred location is the one that gives the more (highly) substituted alkene l.e., the stable alkene.
For example, the dehydration of 3,3 - dimethyl - 2- butanol gives a mixture of alkenes. The secondary carbocation formed in this reaction undergoes rearrangement to form a more stable tertiary carbocation.

(i) An aromatic hydrocarbon A reacts with propene in the presence of anhydrous AICl₃ to give a compound B.

(ii) Compound B undergoes oxidation in the presence of air and hydrogen peroxide to give C.

(iii) Compound C decomposes in HCI acid solution to give compound D and acetone. Identify A, B, C and D. Explain the reactions.

Compound	Compound Name	Formula
A	Benzene	C6H6
B	Cumene
C	Cumene hydroperoxide
D	Phenol	C6H5OH