Alcohols Phenols And Ethers

Isopropylbenzene (cumene) is oxidized in the presence of air to form cumene hydroperoxide (X).

On acidic hydrolysis, cumene hydroperoxide breaks down to give:

• Phenol (Y)
• Acetone (Z)

This reaction is important in industry for the commercial production of phenol and acetone.

Therefore:

X = Cumene hydroperoxide
Y = Phenol
Z = Acetone

Correct Answer:

Correct Answer: (B) cumene hydroperoxide, phenol, acetone

We are given three compounds A, B, and C with the molecular formula . Let's analyze their behavior to identify each compound:

• Compound A and Compound B liberate hydrogen gas with sodium metal: This means both compounds contain a hydroxyl group (–OH), indicating they are either alcohols or phenols.
• Compound B dissolves in sodium hydroxide: This is a property of phenols, which form phenoxide ions in basic solutions. So, B is a phenol.
• Compound C is inert to both sodium metal and sodium hydroxide: This suggests it is neither an alcohol nor a phenol. It is likely an ether, which generally does not react with either.

Now, considering the molecular formula :

• Compound A is likely benzyl alcohol – reacts with sodium but not with NaOH like phenol.
• Compound B is likely cresol (a methylphenol) – reacts with both sodium and NaOH.
• Compound C is likely anisole (methoxybenzene) – an ether that is unreactive in both tests.

Correct Answer:

Correct Answer: (E) Anisole, cresol and benzyl alcohol

When benzyl chloride (C₆H₅CH₂Cl) reacts with magnesium metal in dry ether, it forms a Grignard reagent known as benzylmagnesium chloride (C₆H₅CH₂MgCl).

Upon treatment with water, this Grignard reagent undergoes hydrolysis to form benzyl alcohol (C₆H₅CH₂OH), which is the product 'A'.

Correct Answer:

Correct Answer: (B) Benzyl alcohol

Chloroxylenol: This compound is a chlorinated derivative of phenol. It is commonly used as a disinfectant and antiseptic. The structure of chloroxylenol has a benzene ring with a hydroxyl group (-OH) and a chlorine atom (Cl) attached to it. In option (a), we can see a phenol ring with a chlorine atom attached to the ring at position 4 and a methyl group attached to position 2, which matches the structure of chloroxylenol.

Terpineol: Terpineol is a monoterpene alcohol found in many essential oils. It has a hydroxyl group (-OH) attached to a six-membered cyclohexene ring. The structure in option (c) corresponds to terpineol, as it is a six-membered ring with a hydroxyl group and two methyl groups, which is characteristic of terpineol. Thus, the correct answer is (D), which corresponds to structures (a) and (c).

Both are constituents of Dettol, where chloroxylenol is a primary active ingredient and terpineol is used for its fragrance and mild antiseptic properties.

Therefore, the correct answer is (D), which includes structures (a) and (c).

The acidity of phenols is influenced by substituents that either stabilize or destabilize the phenoxide ion.

• p-Nitrophenol (III) is the most acidic due to the electron-withdrawing nitro group at the para position, which stabilizes the phenoxide ion through resonance.
• m-Nitrophenol (I) is less acidic than p-nitrophenol, but more acidic than phenol due to the electron-withdrawing nitro group, albeit in the meta position, which has less resonance effect.
• Phenol (IV) is more acidic than p-cresol (II) because the hydroxyl group in phenol is a stronger electron-withdrawing group compared to the methyl group in p-cresol.
• p-Cresol (II) is the least acidic because the methyl group is an electron-donating group, which destabilizes the phenoxide ion.\\

The correct option is (A) : (III) > (I) > (IV) > (II)

Resorcinol is a chemical compound consisting of a benzene ring with two hydroxyl groups (-OH) attached to the ring. The positions of the hydroxyl groups determine its name. In the case of resorcinol, the hydroxyl groups are attached to the 1st and 3rd positions on the benzene ring. This gives the compound the name Benzene-1, 3-diol.

The correct option is (A) : Benzene-1,3-diol

When 2, 4, 6-Trinitrochlorobenzene is warmed with water, the chlorine atom is replaced by the hydroxyl group, forming the corresponding phenol. This is because the nitro groups present at the ortho and para positions to the chlorine atom increase the electrophilicity of the carbon attached to the chlorine, making it easier for the nucleophilic substitution to occur with water, leading to phenol formation.

The correct option is (C) : 2, 4, 6-Trinitrochlorobenzene

The acidity of a compound depends on the electronic effects of substituents attached to the aromatic ring (for phenols and derivatives) and the stability of the conjugate base formed after losing a proton.
- o-Nitrophenol (i): The nitro group is an electron-withdrawing group (via both inductive and resonance effects), which increases the acidity of phenol. The ortho position further stabilizes the conjugate base, making it the most acidic among these compounds.
- Phenol (ii): Phenol itself is less acidic than o-nitrophenol, as there are no additional electron-withdrawing groups. The hydroxyl group can donate electrons via resonance, making the conjugate base less stable compared to o-nitrophenol.
- o-Cresol (iii): The methyl group is an electron-donating group via inductive effects, which makes the conjugate base less stable and reduces the acidity of o-cresol.
- Ethanol (iv): Ethanol has a hydroxyl group, but it is not attached to an aromatic ring, and the lack of any additional electron-withdrawing groups makes it the least acidic.
Thus, the correct order of acidity is (i) < (ii) < (iii) < (iv).