Autoionization Reactions are those reactions in which ions or molecules ionizes spontaneously without adding any external reagent.
For Example,
Autoionization of water.
H₂O + H₂O ⇆ H₃O⁺ + OH⁻
Autoionization reaction of Methanol is shown below,
The answer is 1/2 because of how many times does 2 go into 2 which is 1 and how many times 2 can go into 4 which is 2. So 1 would go on top and the 2 would go on the bottom