Question

substance br₂ nf₃
imfs ldf ldf and dipole - dipole
molecular weight 159.8 g/mol 71.0 g/mol
bp 332.4 k 144.15 k
given the above information,
which imf do you think has the
most influence on the difference
in boiling point between the two
substances above?
london dispersion
dipole - dipole
hydrogen bonds

Explanation:

London dispersion forces (LDF) are stronger in \(Br_2\) due to its larger molecular weight (\(159.8\ g/mol\) vs \(71.0\ g/mol\) for \(NF_3\)). Larger molecules have more electrons, leading to stronger LDF. Although \(NF_3\) has dipole - dipole forces in addition to LDF, the difference in boiling points (\(332.4\ K\) for \(Br_2\) and \(144.15\ K\) for \(NF_3\)) is mainly because \(Br_2\) has much stronger LDF. Hydrogen bonds are not present in either (\(H\) - bond requires \(H\) bonded to \(N\), \(O\), or \(F\) and interaction with another \(N\), \(O\), or \(F\)).

Answer:

London dispersion