• # question_answer Correct order of bond angles for the following species is A) $N{{H}_{3}}>PC{{l}_{3}}>BC{{l}_{3}}$ B) $BC{{l}_{3}}>N{{H}_{3}}>PC{{l}_{3}}$ C) $BC{{l}_{3}}>PC{{l}_{3}}>N{{H}_{3}}$ D) $PC{{l}_{3}}>BC{{l}_{3}}>N{{H}_{3}}$

$BC{{l}_{3}}$ is trigonal in shape where bond angle is $120{}^\circ$. In $N{{H}_{3}}$ and $PC{{l}_{3}}$ (both are having pyramidal geometry), though the central atom has equal number of lone pairs and bond pairs, the valence shell of P is relatively bigger, so electrons suffers lesser repulsion and thus bond angle is lower. Thus, the correct order of bond angle is $BC{{l}_{3}}>N{{H}_{3}}>PC{{l}_{3}}$.