Chapter 8, Problem 5STP

Interpretation Introduction

Interpretation: The most polar bond needs to be identified.

Concept Introduction: A bond is polar if there is an electronegativity difference between the atoms bonded together. Here, the atom with high electronegativity will have a partial negative charge, and the atom with low electronegativity will have a partial positive charge. The strength of the polarity of a bond depends on the magnitude of the difference in electronegativity between two atoms.

Answer to Problem 5STP

Option (C)

Explanation of Solution

Reason for the correct option:

In the options, the hydrogen atom is bonded with different halides. Here, the hydrogen atom is the same thus, the difference depends on the electronegativity of halogen atoms. On comparing the electronegativity, fluorine is highly electronegativity and iodine has the lowest electronegativity value. The correct order of increasing electronegativity of halogen is as follows:

  $\text{I}<\text{Br}<\text{Cl}<\text{F}$

Thus, the difference in electronegativity will be maximum in the H-F bond.

Therefore, the H-F bond will be most polar in nature, and option (C) is correct.

Conclusion

Reason for incorrect options:

The order of increasing electronegativity of halogen is as follows:

  $\text{I}<\text{Br}<\text{Cl}<\text{F}$

Here, the H-I bond will be the least polar as I have the lowest electronegativity value among halogens.

Similarly, H-Br and H-Cl bonds will have less polarity as compared to H-F.

Therefore, options (A), (B), and (D) are incorrect.