Using the table of p K a values given in [Appendix I] , answer the following: d. Which is more electronegative: an sp 3 oxygen or an sp 2 oxygen? e. Which compounds demonstrate that the relative electronegativities of a hybridized nitrogen atom are sp > sp 2 > sp 3 ?

Hey, everyone. And welcome back to another video below are the PK values of several nitrogen containing compounds. A determine which one is more electron, an SP three nitrogen or an SP two nitrogen B, which compounds show that a hybridized nitrogen has sp followed by SP two, followed by sp three relative electronegativity. Starting with part A. We just want to look at the table and identify the hybridization of each nitrogen atom. The first compound paladine would have an SP three hybridized nitrogen because there are four electron regions, three sigma bonds and one lone pair on nitrogen that is not shown. Now, the second structure diamite will essentially have an SP two hybridized nitrogen because the long pair of nitrogen is actually delocalized into resonance due to the presence of the adjacent carbon groups. Now, benzyl nitrile would have an sp hybridized nitrogen because nitrogen only has one long pair and one triple bond, that would be two electron regions. And finally, Tylo heal amine, it would have an SP three hybridized nitrogen. Once again, there are three sigma bonds and one lump pair. So now if we consider their PK values, let's remember that PK A the lower it is the greater the acidity, right. So they are inversely proportional. And what we can say is that if we compare our SP three nitrogens to the SP two nitrogen, the PK A of an SP two nitrogen containing compound is actually lower than the PK A values of an SP three nitrogen containing compound or compounds in this case, right? Because we have two of them and we can essentially say that an SP two hybridized nitrogen would produce a more acidic compound, meaning it is expected to be more electron because a higher electronegativity implies a more polarized bond and therefore a more acidic hydrogen. So that we can say that SP two nitrogen is more electron than SP three, right. So we can say that SP two is more electron than SP three. And this is applicable to ni in this case, even though it's also applicable for carbons, for example. So that would be our first answer to this problem. Now, continuing with part B, we can also say that based on this trend, SP is expected to be a more electron nitrogen than SP two or SP three. So essentially, we notice exactly the same pattern because the PK value of benzo nitrile is negative 10, right. So it's the lowest one, meaning sp hybridized nitrogen would produce a greater acidity and therefore, would be considered the most electron. Therefore, we can say that for part B Benson, I trial it would be our first compound which has an sp hybridized nitrogen. This shows us that nitrogen and benzo Nitra would be the most electron negative followed by sp two ones. So first of all, we will start with cyclohexylamine or actually, it would be more correct to say thalami because it has a lower PK value, right. So we are going in an increasing order. So the next one would be tham which has an SP two hybridized nitrogen followed by now, the next one, this is where we add cycle hexamine because the PK value has increased. That would be an SP two hybridized NGEN and finally followed by an SP 31 which is paladine. And as we can see, as the acidity decreases, the hybridization goes from SP to SP two to SP three. So there's a decrease in the S character and therefore, we have shown our pattern. That'll be it for today. Thank you for watching.

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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

3. Acids and Bases

Ranking Acidity

Organic Chemistry

3. Acids and Bases

Ranking Acidity

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Problem 38d,e

Textbook Question

Using the table of pK_a values given in [Appendix I] , answer the following:
d. Which is more electronegative: an sp³ oxygen or an sp² oxygen?
e. Which compounds demonstrate that the relative electronegativities of a hybridized nitrogen atom are sp > sp² > sp³?

Verified step by step guidance

Step 1: Understand the relationship between electronegativity and hybridization. Electronegativity increases with greater s-character in the hybrid orbitals. For example, sp orbitals have 50% s-character, sp2 orbitals have 33% s-character, and sp3 orbitals have 25% s-character. This means sp > sp2 > sp3 in terms of electronegativity.

Step 2: For part (d), identify compounds in Appendix I with hydrogens attached to sp2 oxygen and sp3 oxygen. For example, an sp2 oxygen is found in a compound like a carboxylic acid (R-COOH), while an sp3 oxygen is found in an alcohol (R-OH). Compare their pKa values. Lower pKa values indicate stronger acids, which correspond to more electronegative atoms stabilizing the conjugate base.

Step 3: Analyze the pKa values of the chosen compounds. For example, the pKa of a carboxylic acid (sp2 oxygen) is typically around 4-5, while the pKa of an alcohol (sp3 oxygen) is around 15-18. The lower pKa of the carboxylic acid suggests that the sp2 oxygen is more electronegative than the sp3 oxygen.

Step 4: For part (e), identify compounds in Appendix I that demonstrate the relative electronegativities of sp, sp2, and sp3 hybridized nitrogen atoms. For example, an sp nitrogen can be found in a terminal alkyne (R-C≡N), an sp2 nitrogen in an imine (R2C=NH), and an sp3 nitrogen in an amine (R-NH2). Compare their pKa values.

Step 5: Compare the pKa values of the compounds with sp, sp2, and sp3 hybridized nitrogen atoms. The compound with the sp nitrogen will have the lowest pKa (strongest acid), followed by the sp2 nitrogen, and then the sp3 nitrogen. This trend reflects the increasing electronegativity of nitrogen as the s-character of its hybrid orbitals increases.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Hybridization

Hybridization is the concept in organic chemistry that describes the mixing of atomic orbitals to form new hybrid orbitals. The type of hybridization (sp, sp2, sp3) affects the geometry and bonding properties of molecules. For example, sp hybridization involves one s and one p orbital, resulting in linear geometry, while sp3 involves one s and three p orbitals, leading to tetrahedral geometry.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. In the context of hybridized atoms, electronegativity can vary based on the hybridization state; sp hybridized atoms are generally more electronegative than sp2, which in turn are more electronegative than sp3. This trend is crucial for understanding the acidity of compounds, as more electronegative atoms stabilize negative charges better.

pKa Values

pKa values indicate the strength of an acid in solution, with lower pKa values corresponding to stronger acids. The pKa can provide insight into the stability of the conjugate base formed after deprotonation. By comparing pKa values of compounds with sp2 and sp3 hybridized oxygens, one can infer the relative electronegativities and acidity of the respective functional groups.

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