Ionization of Hydrogen.
In this exercise, we will obtain a rough estimate for the stability of hydrogen. Consider the combination reaction for hydrogen

p⁺ + e⥨H
where p⁺ are protons of mass mₚ, e are electrons of mass mₑ and H is the hydrogen atom of mass mₕ. All particles are in thermodynamic equlibrium in a value V and you can consider all species as an ideal gas