Assertion : The strength of haloacids increases in the order : $\mathrm{HI} \ll \mathrm{HBr} \ll \ma

Question

Assertion : The strength of haloacids increases in the order : $\mathrm{HI} \ll \mathrm{HBr} \ll \mathrm{HCl} \ll \mathrm{HF}$\ Reason : Strength of acid HA depends only on the electronegativity difference between H and $A$.

Professor PC Thomas Classes · Answer

(d) : The correct order of acidic strength is $\mathrm{HF} \ll \mathrm{HCl} \ll \mathrm{HBr} \ll \mathrm{HI}$. While comparing elements in the same group of the periodic table, $\mathrm{H}-\mathrm{A}$ bond strength is a more important factor in determining acidity than its polar nature. As the size of $A$ increases down the group, $\mathrm{H}-A$ bond strength decreases and so the acid strength increases.