Cyanide is quantified by potentiometric titration, a technique broadly used in gold mining. It can also be determined by titration with silver ion. Since There exists a substantial electronegative difference between the N and H across the linear molecule, HCN, or hydrogen cyanide, Hence HCN is actually a polar molecule. https://griffincfebb.bloggazza.com/29636924/the-5-second-trick-for-how-does-potassium-cyanide-work