Hydrogen cyanide, or HCN, is not a strong acid. In solution, hydrogen cyanide is a weak acid that is mostly HCN with minimal amounts of hydronium and cyanide ionized. A weak acid partially ionizes in solution. The solution moves backwards and forwards to create the products and reactants.Continue Reading
As a rule, most acids that begin with H in the chemical formula are weak acids, but there are exceptions.
Hydrogen cyanide has a pKa of 9.2. The carbon has a triple bond with the nitrogen and a single bond with hydrogen. It is a weak acid because the carbon is reluctant to donate the hydrogen atom because the bond keeps the molecule stable. However, the substance is volatile, making it an incredibly toxic gas.Learn more about Acids & Bases