Phosphorus cannot form PH5 with its outer electronic configuration as 3s2, 3p3 because
A.phosphorus cannot show + 5 oxidation state
B.PH5 is not a stable compound.
C.∆aH value of dihydrogen and ∆egH value of✓ Correct
D.phosphorus is not very reactive hence does not
Explanation
5 PH is not stable because the overlapping between 1s- hydrogen and 3p- phosphorous is not so effective. Therefore, no back bonding is possible. Consequently, enthalpy value of hydrogen is not favourable for higher oxidation states of phosphorous.