General introduction of alcohol, Phenol and Ethers Questions in English

(B) An aromatic alcohol is a compound in which the hydroxyl group $(-OH)$ is attached to a carbon atom that is part of a side chain attached to an aromatic ring, not directly to the aromatic ring itself.
$(I)$ Phenol: The $-OH$ group is directly attached to the benzene ring. This is a phenol, not an alcohol.
$(II)$ Benzyl alcohol $(C_6H_5CH_2OH)$: The $-OH$ group is attached to a carbon atom of the side chain. This is an aromatic alcohol.
$(III)$ $m$-Ethylbenzyl alcohol: The $-OH$ group is attached to a carbon atom of the side chain. This is an aromatic alcohol.
$(IV)$ $m$-Ethylphenol: The $-OH$ group is directly attached to the benzene ring. This is a phenol.
Therefore, $(II)$ and $(III)$ are aromatic alcohols.

(A) $1$. $A$ benzylic alcohol is one where the $-OH$ group is attached to a carbon atom that is bonded to a benzene ring.
$2$. $A$ primary benzylic alcohol has the structure $Ar-CH_2OH$, where the carbon atom attached to the $-OH$ group is bonded to only one other carbon atom (the benzene ring).
$3$. In $C_6H_5CH_2OH$ (benzyl alcohol), the $-OH$ group is attached to a $CH_2$ group which is directly bonded to the benzene ring $(C_6H_5)$. Thus, it is a primary benzylic alcohol.
$4$. $C_6H_5 - CH(CH_3)OH$ is a secondary benzylic alcohol.
$5$. The other options are not benzylic alcohols as they lack a benzene ring.

(D) $1$. $A$ phenol is an organic compound in which a hydroxyl group $(-OH)$ is directly attached to a carbon atom of an aromatic ring.
$2$. In options $(A)$, $(B)$, and $(C)$, the $-OH$ group is directly bonded to the benzene or naphthalene ring, making them phenols.
$3$. In option $(D)$, the $-OH$ group is attached to a side-chain carbon $(-CH_2-)$ which is then attached to the benzene ring. This compound is benzyl alcohol, not a phenol.
$4$. Therefore, the correct answer is $(D)$.

(D) benzylic alcohol is one where the $-OH$ group is attached to a carbon atom that is bonded to a benzene ring.
$(1)$ $A$ primary benzylic alcohol has the $-OH$ group on a carbon attached to one other carbon (besides the benzene ring).
$(2)$ $A$ secondary benzylic alcohol has the $-OH$ group on a carbon attached to two other carbons.
$(3)$ $A$ tertiary benzylic alcohol has the $-OH$ group on a carbon attached to three other carbons (one of which is the benzene ring).
In option $D$, the carbon atom bearing the $-OH$ group is directly attached to the benzene ring and two methyl groups. Thus, it is a tertiary benzylic alcohol.

(B) $1$. $A$ dihydric alcohol is an alcohol that contains two hydroxyl $(-OH)$ groups in its molecule.
$2$. Glycerol $(CH_2OH-CHOH-CH_2OH)$ is a trihydric alcohol.
$3$. Ethylene glycol $(HOCH_2-CH_2OH)$ contains two $-OH$ groups, making it a dihydric alcohol.
$4$. Sorbitol $(C_6H_{14}O_6)$ is a hexahydric alcohol.
$5$. Methanol $(CH_3OH)$ is a monohydric alcohol.
$6$. Therefore, the correct option is $B$.

(A) $1$. Crotonyl alcohol is $CH_3-CH=CH-CH_2OH$, which contains only one $-OH$ group.
$2$. Ethylene glycol is $HO-CH_2-CH_2-OH$, which contains two $-OH$ groups.
$3$. Pyrogallol is $1,2,3-trihydroxybenzene$, which contains three $-OH$ groups.
$4$. Hydroquinone is $1,4-dihydroxybenzene$, which contains two $-OH$ groups.
$5$. Therefore, only Crotonyl alcohol contains one $-OH$ group.

(C) $1$. In aromatic alcohols, the hydroxyl group $(-OH)$ is attached to a carbon atom of the side chain of an aromatic ring.
$2$. An example is benzyl alcohol $(C_6H_5CH_2OH)$, where the $-OH$ group is attached to the side chain carbon, not directly to the benzene ring.
$3$. Phenols have the $-OH$ group directly attached to the aromatic ring, whereas aromatic alcohols have it on the side chain.
$4$. Therefore, the correct classification is aromatic alcohols.