\(AlF _3\) shows trigonal symmetric structure due to \(sp ^2\) hybridization.
\(NF _3\) shows pyramidal geometry, having equal bonds due to \(sp ^3\)
\(ClF _3\) shows trigonal bi-pyramidal due to \(dsp ^3\) hybridization, in which all bonds are not equal.
Hence, \(ClF _3\) is the molecule whose bonds are not equal.