Comparing Basicity: -OCH3, -OH, -NH2, and Alkyle with Negative Charge

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SUMMARY

The discussion focuses on the basicity comparison of -OCH3, -OH, -NH2, and an alkyl group with a negative charge. It concludes that -NH2 is the strongest base among the options, with a conjugate acid pKa of approximately 35, significantly higher than that of water (15.7), alcohols (16-18), and ethyne (HCCH, ~25). The relationship between basicity and the pKa of conjugate acids is emphasized as a key method for determining basic strength.

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  • Understanding of acid-base chemistry and pKa values
  • Familiarity with functional groups such as alcohols, amines, and alkyl groups
  • Knowledge of conjugate acids and their relationship to basicity
  • Basic grasp of organic chemistry concepts, including hybridization and molecular structure
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  • Research the concept of pKa and its significance in acid-base chemistry
  • Study the basicity of various functional groups in organic compounds
  • Explore the relationship between hybridization and acidity/basicity
  • Learn about the effects of substituents on the acidity of conjugate acids
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Chemistry students, organic chemists, and anyone interested in understanding the principles of acid-base chemistry and the factors influencing basicity in organic compounds.

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Homework Statement



-OCH3, -OH, -NH2, and the fourth choice is an alkyle, ethyne with a neg charge. the picture shows a triple bond attacked to a hydrogen.

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The Attempt at a Solution



I know that OH is a relatively common base and I thought it was strong, but I have no idea how it compares with the others. I know that alkyles are are less basic than alkenes and alkanes, but the oxygens throw me off a bit. I think that by having O in them it would suggest that their conj acid would be more acidic making them more basic. Is this correct at all? Is there an easy way to determine basicity?
 
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check the pKa of each conjugate acid. whichever has the highest pKa is the strongest base

water = 15.7
alcohols are between 16-18
NH3 is ~35
HCCH is ~25

so NH2- is the strongest base
 

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