Chemistry 9701 · AS & A Level · States of matter

States of matter — practice question

Nitrogen, $\text{N}_2$, and carbon monoxide, $\text{CO}$, each have $M_r = 28$. Nitrogen, $\text{N}_2$, has a boiling point of $77\,$K. Carbon monoxide, $\text{CO}$, has a boiling point of $82\,$K. What might be responsible for this difference in boiling points?

  • ACO molecules have a permanent dipole, the $\text{N}_2$ molecules are not polar.
  • B$\text{N}_2$ has $\sigma$ and $\pi$ bonding, CO has $\sigma$ bonding only.
  • C$\text{N}_2$ has a strong $\text{N}\equiv\text{N}$ bond, CO has a $\text{C}=\text{O}$ bond.
  • DThe CO molecule has more electrons than the $\text{N}_2$ molecule.

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