Will acids really donate a proton? In an atom, the proton is inside the nucleus and I don't think a proton will go all the way out of atom dodging all electrons and enter into the nucleus of the base.

It seem impossible but the Brønsted–Lowry theory says acids donate protons.

I am confused—could someone explain what is actually meant by acids donating protons?


Yes, according to the Arrhenius theory, acids dissociate in aqueous solution and release a proton ($\ce{H+}$). The Brønsted–Lowry defines acids ($\ce{HA}$) and bases ($\ce{B}$) in such a way that their interaction is characterized by the exchange of a proton according to $\ce{HA + B <=> A- + HB}$.

However, this is about the reaction of molecules in which real hydrogen atoms are bound to other atoms.

To illustrate the idea, let's think about the reaction between acetic acid, $\ce{CH3COOH}$, and benzylamine, $\ce{C6H5CH2NH2}$. If we combine both liquids in our imagination, the following will happen:

$\ce{CH3COOH + C6H5CH2NH2 -> CH3COO- + C6H5CH2NH3+}$

The acid donates a proton to the amine, which serves as the base. In the course of this reaction, the acid is converted to its corresponding base, while the base is converted to its corrsponding acid.

You are confusing dissociation and proton exchange with a type of radiocative decay known as proton emission.

  • 3
    $\begingroup$ $\ce{H+}$ is a proton since the nucleus of most hydrogen atoms is just a proton. With its electron gone, the hydrogen cation is a proton. $\endgroup$ – Ben Norris Mar 11 '17 at 17:19
  • $\begingroup$ @BenNorris Though it might be a proton plus a neutron or two, in the case that hydrogen atom is one of the other two isotopes. ;-) $\endgroup$ – David Richerby Mar 11 '17 at 20:44

It donates a Positive Hydrogen Ion. It's basically a Proton but i find this formulation to be less confusing when trying to understand it for the first time.


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