Answer:
Shortest carbon-nitrogen bond = CH3CN, strongest carbon-nitrogen bond = CH3CN
Explanation:
Bond length is defined as the distance between the centers of two covalently bonded atoms, in this case; carbon and hydrogen.
The length of the bond is determined by the number of bonded electrons (the bond order).
The higher the bond order, the stronger the pull between the two atoms and the shorter the bond length.
Therefore, bond length increases in the following order: triple bond < double bond < single bond.
CH3CN - There's a triple bond between Carbon and Nitrogen
CH3NH2 - The bond between carbon and nitrogen is a single bond.
CH2NH - The bond between carbon and nitrogen is a double bond.
The specie with the shortest carbon-nitrogen bond is CH3CN (acetonitrile).
The species with the strongest carbon-nitrogen bond is also CH3CN (acetonitrile) because it contains a triple bond. A triple bond contains one sigma and 2 pi bonds. The energy required to break it is more when compared to the other bonds hence, it is the strongest bond.