An HCN molecule has three covalent bonds.
In HCN, hydrogen (H), carbon (C), and nitrogen (N) form a linear molecular structure. Each atom contributes one electron to form a covalent bond, resulting in a total of three covalent bonds in the molecule.
The hydrogen atom forms a single covalent bond with the carbon atom, and the carbon atom forms a triple covalent bond with the nitrogen atom. The triple bond between carbon and nitrogen consists of one sigma bond and two pi bonds.
The Lewis structure of HCN can be represented as follows:
H:C≡N
Where the ":" represents a shared pair of electrons in a covalent bond, "=" represents a double bond, and "≡" represents a triple bond.
So, HCN has three covalent bonds in total.