Question

Arrange the following oxoacids in the order of their increasing acidic strength:
(A). HOCl
(B). HOCl₂
(C). HOCl₃
(D). HOCl₄
Choose the correct answer from the options given below:

• A. (A), (B), (C), (D)
• B. (A), (C), (B), (D)
• C. (A), (D), (B), (C)
• D. (C), (B), (D), (A)

Hint:

The more electronegative oxygen atoms that are attached to the central atom, the more the electron density of the conjugate base will be delocalized, which increases its stability, thus strengthening the acid.

Answer 1

The Correct Option is C

The acidic strength of oxoacids increases with the number of oxygen atoms attached to the central atom. This is because more oxygen atoms stabilize the conjugate base through resonance.
• HOCl has one oxygen atom
• HOClO has two oxygen atoms
• HOClO2 has three oxygen atoms
• HOClO3 has four oxygen atoms.
The order of increasing acid strength is HOCl <HOClO <HOClO2 <HOClO3. The higher the number of oxygen atoms, the greater the resonance and stabilization of the conjugate base, and thus a stronger acid.