Which is the stronger acid, CH3NH2 or CH3OHAgain, a straightforward What.How to start

QUESTION:

Which is the stronger acid, CH3NH2 or CH3OH?Again, a straightforward What.How to start? When you are asked to evaluate the strength of an acid, look at its conjugatebase. The most stable conjugate base (on the basis of atom electronegativity as well as stabilizinginductive and resonance effects) corresponds to the strongest acid (Section 2-2).So, draw all the possible conjugate bases by removing a proton (H1) from every locationin each molecule:CH2NH2 CH CH2OH 3NH CH3OWhich is the most stable conjugate base? These four species have negative charges on threedifferent atoms: C, N, and O. How do these atoms differ?Information needed! The three atoms differ in their respective electronegativity:O . N . C (Table 1-2). The more electronegative an atom is, the better it is at attractingelectrons. The most electronegative atom therefore stabilizes best the extra electron pair andnegative charge in the corresponding conjugate base.Finally, Proceed logically: (1) Oxygen is the most electronegative in the trio, so, withthe extra electron pair and negative charge on O, CH3O:2 is the most stable of the fourconjugate bases above. (2) Given that conclusion, CH3OH must be the stronger acid, andthe hydrogen on the oxygen must be the most acidic of its four hydrogen atoms. Energy: Energy change is one of the fundamental principles governing chemical reactions.Breaking bonds requires energy input; making bonds releases energy. DH8 5 (energy in) 2(energy out). The equilibrium is favored in the direction of reaction for which DG8 isnegative, which will often be determined by a negative DH8 (at least when DS8 is small).