# Question #703cc

$P {H}_{3}$ is more polar among the three other compounds.
According to Fajan's rule when a cation is small in size and anion is very large in size then polarization occurs. Since $S b$ is large in size ,hence in $S b {H}_{3}$ more polarization occurs. Then it behaves as covalent compound.For having small size of Phosphorous, less polarization occurs.So ,we can say that phosphine is more polar than arsine, similarly arsine is more polar than stibine and stibine is covalent in character.