Understanding Acid Strength: Comparing Methanol and Methanamine

[gaganpreetsingh]

I have two organic compounds, Methanol and Methanamine (CH3OH and CH3NH2). The question is to predict their relative acidity. I reasoned in this way. Oxygen is more electronegative than hydrogen. So methanol will bond the hydrogen more tightly since bond strength is directly proportional to the electronegative difference. So it will be difficult for it to give away it's Hydrogen. So it must be less acidic. But the answer is just the opposite. So what is wrong with my reasoning.

 

[bomba923]

Remember that acidic dissociation of methanol is [tex] C H_3 OH + H_2O \rightleftharpoons H_3 O ^ {+} \, (aq) + CH_3 O^{-}\,(aq) [/tex].

Oxygen is more electronegative than nitrogen, and will more favorably hold a negative charge than would nitrogen. Nitrogen will actually be more reluctant to release this hydrogen as a cation.

Methamine, on the other hand, would more likely react as:
[tex] CH_3NH_2 + H_2O \, \rightleftharpoons CH_3 NH_3^{+} \, (aq) + OH^{-} \, (aq)[/tex].

 

[ravenprp]

Your reasoning is correct in terms of electronegativity and bond strength. However, when comparing the acidity of two compounds, we need to consider the stability of the resulting conjugate base. In this case, the conjugate base of methanol (CH3O-) is more stable than the conjugate base of methanamine (CH3NH-), due to the presence of the more electronegative oxygen atom. This means that methanol is actually the stronger acid, as it is more likely to donate its proton and form a stable conjugate base. So, while bond strength is an important factor, it is not the only factor that determines the acidity of a compound. Other factors, such as the stability of the conjugate base, also play a role.