CGPET 2022 Solved Paper

According Bronsted concept of acid and base, strongest acid form weakest conjugate base. HClO4 is strongest and HOCl is weakest acid.
ClO4−<ClO3−<ClO2−<ClO− is the correct increasing order of Bronsted base strength with an increase in the number of oxygen atoms, the extent of delocalization of negative charge by pπ−dπ bonding increases.