Question

Arrange in ascending order of acidity

Answer 1

This question is totally based on the concept of substituents attached on the benzene ring. We will define the order of acidity on the basis of positions like ortho-, meta-, and para. So, it can be arranged in ascending order of acidity.

Complete Solution :
-First, we can see there are four structures of benzene ring with OH group, and COOH group attached at the different positions making it a different structure.
-Now, if we talk about (I) structure, then we can see there is di-substitution of phenol (OH) group at the ortho- position i.e. due to the presence of electron withdrawing group (COOH), that will increase the acidity of the compound. This compound is stabilized by hydrogen bonding from both the alcohol groups hence will be most acidic.
-If we look at (II) structure, then the phenol group is present at the meta position, making it the least acidic compound.
-Now, talking about the structure (III), the phenol group is present at the ortho-position, and the delocalization of negative charge will be there, so it will be more acidic than that of meta. Ortho-substituted benzoic acids are stronger acids than their meta and para isomers, irrespective of the nature of ligand. Hence, will be the second most basic compound.
-We have the last structure (IV), in that phenol group is attached at the para position, and it will be more acidic than that of meta, and less acidic than that of ortho due to the formation of a phenoxide ion, and leading to the formation of resonating structure.
-Thus, in the last we can conclude that the ascending order of acidity is (II) < (IV) < (III) < (I).

Note: - Internal energy of an ideal gas depends only on the temperature.
- If a real gas is suddenly expended by moving the piston outward, there will be a decrease in the temperature of the gas.