The strongest acid is fluoroantimonic acid which is a mixture of hydrogen fluoride and antimony pentafluoride.
Fluoroantimonic acid is called a super acid because of it's extreme acidity and is significantly stronger than other common types of acids.
Fluroantimonic acid is formed by combining antimony pentafluoride (SbF5) and hydrogen fluoride (HF).
Spectroscopic measurements also show that fluoroantimonic acid consists of a mixture of HF-solvated protons, [(HF) nH] + (such as H 3F+2), and SbF5-adducts of fluoride, [(SbF5)nF]â (such as Sb 4Fâ21).
Thus, the formula " [H 2F] +[SbF 6] â" is a convenient but oversimplified approximation of the true composition.
Despite its overwhelming strength, fluoroantimonic acid has an Achilles' heel.
It can't erode polytetrafluoroethylene (PTFE), commonly known as Teflon.
Thus, Teflon containers are the chosen vessels to store this potent liquid.
Hydrocyanic acid is the weakest acid with the $p{{K}_{a}}$ value of $9.2$ .
It partially ionises in water to give hydrogen ion and cyanide ions.
The cyanide ion is the strongest conjugate base. The hydrocyanic acid is then represented as $HCN$ .