Explain why CH 3 Cl has a greater dipole moment than CH 3 F even though F is more electronegative than Cl.

Hello everyone. So in this video, we want to explain why chloral benzine has a smaller depot moment compared to cycle hex a chloride. So the ability of an atom to attract the shared pair of electrons towards itself is what we call electro negativity typo moments occurring bonds. As a result of differences in the electro negativity ease of the bonded atoms. The difference in electro negativity results in the separation of charge creating what we call a dipole moment. This typo moment of a bond is defined as the product of magnitude of charge and the distance between the charges. So charges affected by electro negativity difference between the two atoms are dipole moment of molecules is based on the magnitude and direction of each individual bond. I pull electro negativity of sp two hybridized carbon in chloral benzine is greater than the sp three hybridized carbon and cycle Hexcel chloride. So let's go ahead and actually write this part out. So how we symbolize the electro negativity difference is by delta lower case E capital N. So this delta here that just means a difference in or change in. And then for E N, that's just our shorthand notation for writing out the word electro negativity. So again, the delta E N or the change in other electro negativity of R S P two hybridized carbon is going to be greater than that of R S P three hybridized carbon in our cycle hex. So chloride, so maybe let's actually write that part out as well. So we said that this is our Cyclo Hexcel chloride And then for SP two, that is our chlor oh benzene. All right. So the results in a lower difference in electric negativity of the carbon chlorine bond and chloral benzine. This bond here has a partial double character as a result of the de localization of the lone pairs of chlorine over the benzene ring in our cycle hexen chlorine molecule, the carbon chlorine bond is a true single bond. This results or this reduces the distance between the charges of the CCL bonds and our chloral benzine molecule. So the type of moments of a bond is the product of the magnitude of the charge and the distance between the charges. Thus, due to the smaller electro negativity difference and smaller bond length of the C cl bond in chloral benzine, it has a smaller depot moments then cycle heads of chloride. So what we just said here and looking at all these four different statements that are provided, the one that best fits what we just described is going to be answer choice D. So this just reads due to the smaller electro negativity difference and smaller bond length of the chlorine carbon bond of chloral benzine. So this explains why chloral benzine has a smaller depot moment compared to the cycle hex a chlorine molecule.

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1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

1. A Review of General Chemistry

Electronegativity

Organic Chemistry

1. A Review of General Chemistry

Electronegativity

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3:06 minutes

Problem 76

Textbook Question

Explain why CH₃Cl has a greater dipole moment than CH₃F even though F is more electronegative than Cl.

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The dipole moment (μ) is a vector quantity that depends on two factors: the magnitude of the charge separation (Δq) and the distance (d) between the charges. It is calculated using the formula:

μ = Δ q \times d

Fluorine (F) is more electronegative than chlorine (Cl), meaning it creates a larger charge separation (Δq) when bonded to carbon. However, the bond length (d) of the C-F bond is shorter than that of the C-Cl bond due to the smaller atomic radius of fluorine.

In CH3Cl, the C-Cl bond has a longer bond length compared to the C-F bond in CH3F. This longer bond length increases the distance (d) in the dipole moment equation, which can compensate for the slightly smaller charge separation (Δq) caused by the lower electronegativity of chlorine.

As a result, the dipole moment of CH3Cl is greater than that of CH3F because the longer bond length of the C-Cl bond contributes more significantly to the overall dipole moment, even though fluorine is more electronegative.

This demonstrates that both electronegativity and bond length must be considered when comparing dipole moments, as the dipole moment is influenced by the product of these two factors.

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Key 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. Fluorine (F) is the most electronegative element, meaning it strongly attracts electrons compared to chlorine (Cl). However, electronegativity alone does not determine the overall dipole moment of a molecule, as the molecular geometry and bond angles also play significant roles.

Dipole Moment

The dipole moment is a vector quantity that measures the separation of positive and negative charges in a molecule. It is influenced by both the electronegativity of the atoms involved and the geometry of the molecule. A higher dipole moment indicates a greater polarity, which can arise from the arrangement of bonds and the overall shape of the molecule, not just the electronegativity of individual atoms.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. In the case of CH3Cl and CH3F, the spatial arrangement of the hydrogen and halogen atoms affects how the dipole moments of the individual bonds combine. The tetrahedral shape of both molecules leads to different resultant dipole moments, with CH3Cl having a greater overall dipole moment due to the specific orientation and bond angles.

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Explain why CH3Cl has a greater dipole moment than CH3F even though F is more electronegative than Cl.

Key Concepts

Electronegativity

Dipole Moment

Molecular Geometry

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Explain why CH₃Cl has a greater dipole moment than CH₃F even though F is more electronegative than Cl.