Determining When Molecular Compounds Ionize When Dissolved Into Water

[Mazurka]

Hello,

This is a matter I have been having some difficulties with for the past few days. My question: How is it that I would go about distinguishing molecular compounds in regards to their capacity to ionize and yield hydrogen ions when dissolved into distilled water?

For example, if ethanol (C₂H₅OH) was dissolved into water, why couldn't the hydrogen atom in the compound ionize and result in the formation of an acid? Couldn't the -OH bond dissociate and result in the formation of a base? Similarly, why is it that methane (CH₄) or sucrose (C₁₂H₂₂O₁₁) cannot ionize and yield hydrogen ions?

This may be common knowledge and I may have been merely mislead. However, I am enrolled in a high school program and I understand that at this level, a lot of details in the sciences are simply left out. I greatly appreciate any clarity or enlightenment anyone can offer me.

Thank you,

Eric.

 

[DrStupid]

For example, if ethanol (C₂H₅OH) was dissolved into water, why couldn't the hydrogen atom in the compound ionize and result in the formation of an acid?

It can, but the pKs is 15,90. Thant means the equilibrium C2H5OH + H2O <=> C2H5O- + H3O+ is almost on the left side.

Couldn't the -OH bond dissociate and result in the formation of a base?

It can, e.g. C2H5OH + Na -> C2H5ONa + ½ H2

Similarly, why is it that methane (CH₄) or sucrose (C₁₂H₂₂O₁₁) cannot ionize and yield hydrogen ions?

C in CH4 is not as interested in the electrons of hydrogen as for example Cl in HCl. In simple molecules acidity is mainly caused by the electronegativity. In complex molecules (e.g. with delocalized electrons) there might be other mechanisms too.