Question

using the structure of the molecule and the IUPAC nomenclature rules, predict the name of the ternary molecule HCN A) hydrocyanic acid B) the two nonmetals indicate that covalent naming rules apply C) the name of the anion predicts the name of the final molecule D) the lack of oxygen in the anion indicates the prefix "hydro-" is used

Answer 1

Answer is: hydrogen cyanide (formonitrile).
Anion CN⁻ is cyanide. Cyanide consists of a carbon atom triple bonded to a nitrogen atom (C≡N).
Hydrogen cyanide is  colorless, poisonous liquid, also weakly acidic.  Salts of the cyanide anion are called cyanides.