A polar covalent bond is a type of chemical bond where a pair of electrons is unequally shared between two atoms. This occurs when one atom has a higher electronegativity than the other, causing a partial positive charge on one atom and a partial negative charge on the other.
Among the options provided:
- a) H-B: This is not a valid chemical bond.
- b) Cl-Br: Chlorine (Cl) and Bromine (Br) have similar electronegativities, so this bond is nonpolar.
- c) S-Cl: Sulfur (S) and Chlorine (Cl) have different electronegativities, making this a polar covalent bond.
- d) C-I: Carbon (C) and Iodine (I) have different electronegativities, but the difference is not as significant as in the case of S-Cl, making this bond less polar.
Therefore, the correct answer is c) S-Cl, as it is the most polar covalent bond among the given options.