Textbook Question
Which of the following has
a. the most polar bond?
b. the least polar bond?
NaI LiBr Cl2 KCl
1. A Review of General Chemistry
Electronegativity
2:23 minutesProblem 57d
Textbook Question
Rank the bonds from most polar to least polar.
d. C—H, C—C, C—N
Verified step by step guidance1
Step 1: Understand the concept of bond polarity. Bond polarity arises due to the difference in electronegativity between the two atoms involved in the bond. The greater the difference in electronegativity, the more polar the bond.
Step 2: Recall the electronegativity values of the elements involved. Approximate electronegativity values are: Carbon (C) = 2.5, Hydrogen (H) = 2.1, and Nitrogen (N) = 3.0.
Step 3: Calculate the electronegativity difference for each bond: (1) For C—H, the difference is |2.5 - 2.1|. (2) For C—C, the difference is |2.5 - 2.5|. (3) For C—N, the difference is |2.5 - 3.0|.
Step 4: Compare the electronegativity differences. The bond with the largest difference is the most polar, and the bond with the smallest difference is the least polar.
Step 5: Rank the bonds from most polar to least polar based on the calculated electronegativity differences: C—N > C—H > C—C.
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Video duration:
2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electronegativity
Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. The difference in electronegativity between two bonded atoms determines the polarity of the bond; larger differences result in more polar bonds. For example, carbon (C) has a lower electronegativity than nitrogen (N), leading to a more polar C—N bond compared to C—C or C—H bonds.
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Bond Polarity
Bond polarity refers to the distribution of electrical charge across a bond between two atoms. A polar bond occurs when there is an unequal sharing of electrons due to differences in electronegativity, resulting in partial positive and negative charges. In the context of the given bonds, the C—N bond is the most polar, followed by C—H, and C—C, which is nonpolar.
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Dipole Moment
The dipole moment is a vector quantity that represents the polarity of a bond, calculated as the product of the charge difference and the distance between the charges. A higher dipole moment indicates a more polar bond. In the ranking of the bonds provided, the C—N bond has the highest dipole moment due to the significant electronegativity difference, while C—C has the lowest due to equal electronegativities.
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