What is the molecular shape of HCN? bent linear angular trigonal pyramidal
The Correct Answer and Explanation is:
The molecular shape of HCN (hydrogen cyanide) is linear.
Explanation:
- Lewis Structure:
- Hydrogen cyanide consists of a hydrogen atom (H), a carbon atom (C), and a nitrogen atom (N). The carbon atom is the central atom, and it forms a triple bond with nitrogen (C≡N) and a single bond with hydrogen (H-C).
- In this arrangement, hydrogen is bonded to carbon, and carbon is bonded to nitrogen through a triple bond. The nitrogen atom has a lone pair of electrons.
- Electron Domain Geometry:
- The central atom, carbon, has two regions of electron density: one from the C-H bond and the other from the triple bond to nitrogen. Both are bonding regions, with no lone pairs on carbon.
- Nitrogen has one lone pair and forms a triple bond with carbon. The lone pair does not affect the molecular shape of the overall molecule significantly.
- VSEPR Theory:
- According to Valence Shell Electron Pair Repulsion (VSEPR) theory, the electron pairs around the carbon atom will arrange themselves to minimize repulsion.
- Since there are only two regions of electron density around the carbon (the C-H bond and the C≡N bond), the molecule adopts a linear geometry, with the H-C≡N bond angle being approximately 180°.
- Molecular Shape:
- Because there are no lone pairs on the central carbon atom and the bonding regions are aligned straight along a single axis, HCN has a linear molecular shape.
Thus, the shape of HCN is linear, and the molecule is essentially a straight line from hydrogen to nitrogen.
