Which is the strongest acid in the following?
- HClO4
- H2SO3
- H2SO4
- HClO3
Answer
(1) HClO4
Solution
Acid strength of oxoacids increases with the electronegativity of the central atom and with its oxidation state.
∵ Cl is more electronegative than S, chlorine oxoacids are stronger than sulphur oxoacids.
Among HClO4 (Cl: +7) and HClO3 (Cl: +5), the conjugate base ClO4- is most stabilised by resonance.
∴ HClO4 is the strongest acid.
Answer: (1)