Question

Bond strength of Hydrogen halides decreases in the order:

• A. $H-F>H-I>H-Br>H-Cl$
• B. $H-Cl>H-F>H-Br>H-I$
• C. $H-F>H-Cl>H-I>H-Br$
• D. $H-F>H-Cl>H-Br>H-I$

Answer 1

The correct option is D $H-F>H-Cl>H-Br>H-I$

Due to decrease in electro negativity bond strength of halo acids decreases from F to I. What is electronegativity? It can be viewed as the ability of the atom to pull electrons. Fluorine, being the most electronegative atom and having a small atomic size, tends to form very strong bond with the Hydrogen atom. Two smaller atoms have a greater tendency to overlap than a small Hydrogen atom and a bigger atom.
Therefore bond strength of halo acids decreases in the order $H-F>H-Cl>H-Br>H-I$.