Is Methanol (CH₃OH) a Strong or Weak Acid?

Is Methanol (CH₃OH) a strong or weak acid?

Methanol is a very weak acid, similar in strength to water. Alcohols can lose their O-H proton to strong bases like NaH or NaNH2, but they do not dissociate appreciably on their own.

FormulaCH₃OH
NameMethanol
CategoryWeak acid
pKa15.5
ConjugateMethoxide ion (CH₃O⁻)
Key ConceptAlcohol as very weak acid

Definition

Methanol is an extremely weak Bronsted-Lowry acid. Its O-H proton can be donated to very strong bases, but it barely dissociates in water.

Acidic Proton / Active Site

The O-H hydrogen is the acidic proton. The C-H hydrogens on the methyl group are not acidic (pKa ~50).

Conjugate Pair

CH3OH -> CH3O- + H+. The methoxide ion (CH3O-) is a strong base because it is the conjugate base of a very weak acid.

Strength Classification

pKa = 15.5, nearly identical to water (15.7). Methanol is about as acidic as water. It only donates a proton to very strong bases like sodium hydride (NaH).

See acidic protons, conjugate base overlays, and pKa labels on interactive 3D molecules.

Explore Methanol's Acid-Base Properties in 3D

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