# What happens to the H electron during acid reaction?

In this generic acid-base reaction:

$\ce{HX + B <=> X- + HB+}$

It's explained that the acid HX donates a proton H+ to its conjugate base HB+. What happens to the electron that was originally in the acid's H atom?

• "What happens to the electron that was originally in the acid's H atom?" It's stuck as an extra electron with the $X$ atom, and that explains why $\ce{X}$ ends up with a uninegative charge. – Gaurang Tandon Feb 5 '18 at 2:21

The electron belonging to elemental hydrogen forms part of a covalent bond with $\ce{X}$. In this acid-base reaction the $\ce{HX}$ bond breaks heterolytically, meaning that both electrons constituting the bond go to $\ce{X-}$, hence the negative charge.
The base then donates electrons to the proton, forming the electron deficient species $\ce{HB+}$.