Step 1: Understanding the Concept:
The acidic strength of any organic molecule is defined by the ease with which it can release a proton (\(H^{+}\)) to a base and the relative stability of the resulting conjugate base.
For the compounds in question (alcohols, water, and phenol), the acidity is determined by the stability of the alkoxide (\(RO^{-}\)), hydroxide (\(OH^{-}\)), and phenoxide (\(C_{6}H_{5}O^{-}\)) ions respectively.
A more stable conjugate base corresponds to a stronger parent acid because the equilibrium of the dissociation reaction shifts further to the right.
The stability of these anions is influenced by electronic effects such as the inductive effect (\(+I\) or \(-I\)) and resonance effects.
Step 2: Detailed Explanation:
To analyze the provided compounds, we must compare the electronic environment surrounding the oxygen atom in their conjugate bases.
1. Alcohols (Propan-1-ol and Propan-2-ol):
In aliphatic alcohols, the hydroxyl group is attached to alkyl groups. Alkyl groups are electron-donating by nature, which is known as the \(+I\) effect.
When an alcohol loses a proton, it forms an alkoxide ion. The electron-donating alkyl groups push electron density toward the already negatively charged oxygen atom.
This increase in electron density destabilizes the alkoxide ion, making it a stronger base and thus its parent alcohol a weaker acid.
In Propan-2-ol (\(CH_{3}-CH(OH)-CH_{3}\)), there are two methyl groups directly contributing to the \(+I\) effect on the carbon atom bearing the oxygen.
In Propan-1-ol (\(CH_{3}-CH_{2}-CH_{2}OH\)), the propyl group provides a \(+I\) effect, but it is less concentrated than the branched structure of Propan-2-ol.
Branching increases the inductive electron donation. Therefore, the isopropoxide ion is less stable than the n-propoxide ion.
Consequently, Propan-2-ol is less acidic than Propan-1-ol.
2. Water:
Water (\(H-OH\)) dissociates to form a hydroxide ion (\(OH^{-}\)). Unlike alcohols, water has no electron-donating alkyl groups attached to the oxygen.
Since there is no \(+I\) effect to further destabilize the negative charge on the oxygen, the hydroxide ion is more stable than aliphatic alkoxide ions.
Therefore, water is a stronger acid than both Propan-1-ol and Propan-2-ol.
3. Phenol:
Phenol (\(C_{6}H_{5}OH\)) is significantly more acidic than water and simple alcohols.
Upon losing a proton, it forms the phenoxide ion (\(C_{6}H_{5}O^{-}\)).
In the phenoxide ion, the negative charge on the oxygen atom is not localized. Instead, the lone pair on the oxygen is in conjugation with the pi-electron system of the benzene ring.
This results in the delocalization of the negative charge over the ortho and para positions of the ring through resonance.
The resonance stabilization of the phenoxide ion is a very powerful effect that makes the ion highly stable.
Because the conjugate base is so stable, phenol readily releases its proton, making it the most acidic compound in the list.
The final order from weakest to strongest acid is: Propan-2-ol < Propan-1-ol < Water < Phenol.
Step 3: Final Answer:
The compounds arranged in increasing order of acidic strength are Propan-2-ol, Propan-1-ol, Water, and Phenol.
This matches Option (B).