Answer Happy

Question 1. For the following pairs of acids, choose the stronger acid and the correct explanation. Fill in the chart to answer the question (Concept: The more stable the conjugate base, the more the equilibrium is shifted to the products, making the acid more acidic. Look for the differences between the pairs of molecules. How is the charge on the conjugate base stabilized?) OH 7 OH 8 13 CHINH, 14 CH₂OH 1 OH 2 Xo CI OH 10 16 SH H 6 (CH3)₂CHOH 12 NH₂ 18 Stronger Acid Correct Explanation 18 Marks total 1 or 2 2 Marks 3 or 4 2 Marks 5 or 6 2 Marks 7 or 8 2 Marks 9 or 10 2 Marks 11 or 12 2 Marks 13 or 14 2 Marks 15 or 16 2 Marks 17 or 18 2 Marks a) Because induction is transmitted through sigma bonds, the closer the electronegative atom is to the acidic atom or group, the more acidic the molecule is b) Since a negatively charged atom farther on the right of the periodic table is more electronegative than the atom on the left of the periodic table, the acid with that obtains a negative charge on the more electronegative atom is more acidic. - no other factors are involved c) An sp carbanion is a weaker base than an sp³ amide ion. (this is the one you need to memorize) d) As the acid functional group becomes more sterically hindered by adjacent alkyl groups, the compound's acidity decreases because of poor solvation of the conjugate base, which causes the equilibrium to be shifted more to the reactants. Or alkyl groups are electron-donating and destabilize the conjugate base's negative charge. e) Because induction is transmitted through sigma bonds, increasing the electronegativity of the atom adjacent to the negatively charged region of the conjugate base decreases its basicity and increases the acidity of the acid f) Resonance of the conjugate base's negative charge onto electronegative atoms is more stabilizing than resonance onto less electronegative atoms. g) A larger negatively charged atom is more stable than a smaller negatively charged atom because the charge on the larger atom is spread over a larger volume, is more polarizable, and has a lower charge density. Thus the stronger acid will have the charge on the conj. base with the larger atom. (no other factors considered). h) Delocalization of the negative charge onto more atoms stabilizes the conjugate base and shifts the equilibrium to products making it a stronger acid. (for both acids, the conj. base anion resonance occurs on atoms of equal electronegativity) i) As the conjugate base's hybridization changes from sp³ to sp² to sp, the basicity of the conjugate base decreases, and the acidity of the acid increases. SH 3 5 (CH3)2CHSH Fill in the chart: 11 Answer OH -H OH 15 F. 17 OH -H OH