Which pair of atoms has the most polar bond?

(1) H-Br

(2) H-Cl

(3) I-Br

(4) I-Cl

For the question given above, option 2 which is H-Cl pair of atoms has the most polar bond among the four of them.

The larger the value of the electronegativity, the greater the atom’s strength to attract a bonding pair of electrons. Hydrogen has an electronegativity of 2.1, and chlorine has an electronegativity of 3.0. The electron pair that is bonding HCl together shifts toward the chlorine atom because it has a larger electronegativity value.