Final answer:
The cyanide ion has a linear molecular geometry, as indicated by its carbon-nitrogen triple bond and the 180° angle between the two atoms.
Step-by-step explanation:
The cyanide ion has which of the following molecular geometries? The correct answer is B. Linear. This can be explained by considering the valence shell electron pair repulsion (VSEPR) theory. Both the carbon and nitrogen atoms in the cyanide ion have a triple bond between them and one lone pair each. The electron-pair geometry is linear, resulting in a molecular structure that is also linear, meaning the ion has an angle of 180° between the carbon and nitrogen atoms. This matches the typical linear geometry for molecules with a central atom bonded to only two other atoms and no lone pairs affecting the geometry.