Chemistry - Complete Pblock- Question with Solution | TestHub

$\mathrm{H}\mathrm{O}\stackrel{+1}{\mathrm{C}\mathrm{l}}<\mathrm{H}\stackrel{+3}{\mathrm{C}\mathrm{l}}{\mathrm{O}}_2<\mathrm{H}\stackrel{+5}{\mathrm{C}\mathrm{l}}{\mathrm{O}}_3<\mathrm{H}\stackrel{+7}{\mathrm{C}\mathrm{l}}{\mathrm{O}}_4$
As the number of oxygen atom increases, an increasing amount of electron density shifts from Cl atom to more electronegative O atom. Hence as the oxidation number of Cl atom increases, the amount of actual positive charge on Cl atom increases which in turn attracts the electron density from$\mathrm{O}-\mathrm{H}$bond, hence the$\mathrm{O}-\mathrm{H}$bond is weakened and proton is easily released and acidity increases.