Polar Covalent Bond Examples: 47 Problems with Answers

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Polar Covalent Bond.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A covalent bond in which electrons are shared unequally between two atoms because of a difference in their electronegativities, creating a partial positive charge (δ+) on the less electronegative atom and a partial negative charge (δ−) on the more electronegative atom.

Two atoms sharing electrons, but one pulls harder — like a tug of war where one side is stronger.

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How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Polar Covalent Bond starts by identifying valence electrons, likely charges or sharing, and the structure that follows.

Common stuck point: Students often know a formula related to polar covalent bond but skip the recognition step: Am I explaining a substance by electron behavior, bond type, molecular shape, polarity, or attractions between particles? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I explaining a substance by electron behavior, bond type, molecular shape, polarity, or attractions between particles?

Worked Examples

Example 1

medium
Two atoms X and Y have ENs of 3.4 and 0.9. Classify the X-Y bond.

Answer

ionic

First step

1
ΔEN=3.4−0.9=2.5.

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Example 2

hard
Calculate ΔEN for the Mg-Br bond and classify it. (EN: Mg 1.3, Br 2.8)

Example 3

hard
A bond between two atoms has measured dipole moment 1.46 D and length 0.92 Å. Estimate the partial charge magnitude. (1 D ≈ 3.336×10−30 C·m)

Example 4

challenge
A bond has 50% ionic character based on Pauling's relation 1−e−(ΔEN)2/4. Estimate ΔEN.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
In a polar covalent bond, are electrons shared equally or unequally?

Example 2

easy
What symbol denotes the partial negative charge on the more electronegative atom?

Example 3

easy
Is the bond in H2 polar or nonpolar covalent?

Example 4

easy
Which atom is δ+ in the H-Cl bond (Cl more electronegative)?

Example 5

easy
Does a polar covalent bond involve electron transfer or electron sharing?

Example 6

easy
Is the O-H bond polar covalent? (O = 3.5, H = 2.1)

Example 7

easy
Which direction does the bond dipole arrow point in a polar covalent bond?

Example 8

easy
Between a C-C bond and a C-O bond, which is polar covalent?

Example 9

medium
Rank the bonds C-H, O-H, and F-H by increasing polarity (EN: H 2.1, C 2.5, O 3.5, F 4.0).

Example 10

medium
A bond has ΔEN=0.9. Classify it (cutoffs: ~0.5 polar, ~1.7 ionic).

Example 11

medium
Does CO2 have polar bonds? Is the molecule polar?

Example 12

medium
In the polar bond N-H, estimate the partial charges' direction (N = 3.0, H = 2.1).

Example 13

medium
Why is a Si-O bond (ΔEN=1.7) considered borderline between polar covalent and ionic?

Example 14

medium
Is the bond in Cl2 polar or nonpolar, and why?

Example 15

medium
Order the bonds H-F, H-Br, H-I by decreasing polarity (EN: H 2.1, F 4.0, Br 2.8, I 2.5).

Example 16

medium
Is the bond in O2 polar or nonpolar, and why?

Example 17

medium
In H2O, are the O-H bonds polar, and does the molecule have a net dipole?

Example 18

challenge
Predict whether CHCl3 (chloroform, tetrahedral) is polar, given C-H is nearly nonpolar and C-Cl is polar.

Example 19

challenge
Explain why CCl4 is nonpolar even though each C-Cl bond is strongly polar.

Example 20

challenge
A diatomic molecule has ΔEN=0 yet a measurable dipole moment is reported. What must be wrong, and what is the true dipole?

Example 21

easy
Which atom in the H-Br bond carries the partial negative charge? (EN: H = 2.1, Br = 2.8)

Example 22

easy
Is the bond in N2 polar or nonpolar?

Example 23

easy
Classify the C-F bond. (EN: C = 2.5, F = 4.0)

Example 24

easy
Which bond is the LEAST polar: C-H, C-Cl, or C-O?

Example 25

easy
Does a polar covalent bond involve complete electron transfer?

Example 26

easy
Classify the bond in HI as polar or nonpolar. (EN: H = 2.1, I = 2.5)

Example 27

medium
Rank the bonds N-H, P-H, As-H by decreasing polarity. (EN: H 2.1, N 3.0, P 2.1, As 2.0)

Example 28

medium
In HClO (H-O-Cl), which bond is more polar: O-H or O-Cl? (EN: H 2.1, O 3.5, Cl 3.0)

Example 29

medium
Why is the C-O bond polar covalent while the C-S bond is nearly nonpolar?

Example 30

medium
Predict which is the most polar bond in formaldehyde, H2C=O: C-H or C=O? (EN: H 2.1, C 2.5, O 3.5)

Example 31

medium
Indicate δ+/δ− for the bond Si-O. (EN: Si = 1.8, O = 3.5)

Example 32

medium
Rank the H-X bonds (X = F, Cl, Br) by increasing bond polarity.

Example 33

medium
In the bond P-Cl (EN: P 2.1, Cl 3.0), label the partial charges.

Example 34

medium
Two atoms have EN 2.55 and 3.04. Is the bond best described as nonpolar, polar covalent, or ionic?

Example 35

medium
Which bond has the larger dipole moment: H-F (μ ≈ 1.83 D) or H-Cl (μ ≈ 1.08 D)?

Example 36

hard
Why does HF have a higher boiling point than HCl even though both have a single polar covalent bond?

Example 37

hard
Predict the direction of the overall dipole in CH3F. (EN: C 2.5, H 2.1, F 4.0)

Example 38

hard
Percent ionic character roughly tracks ΔEN. Estimate it qualitatively for H-F vs C-H.

Example 39

hard
If ΔEN is large but the bond is between two main-group nonmetals, is the bond considered ionic?

Example 40

hard
BeCl2 has ΔEN=1.5 but exists as a covalent linear molecule in the gas phase. Why is the simple ΔEN rule misleading here?

Example 41

hard
In SO2, identify whether the S-O bond is polar and whether the molecule has a net dipole.

Example 42

challenge
Rank the bonds H-F, Li-F, K-F by ionic character.

Example 43

challenge
Explain why CO has a small dipole moment (0.11 D) despite a large ΔEN between C and O.
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Background Knowledge

These ideas may be useful before you work through the harder examples.

covalent bondelectronegativity