Which of the following has least covalent `P-H` bond

Options

A. `PH_(3)`
B. `P_(2)H_(6)^(2+)`
C. `P_(2)H_(5)^(+)`
D. `PH_(4)^(+)`

Answer

B

Explanation

More the formula charge distributed on each P-H bond lesser is the covalent character. Formal charge distributed (F.C.D) on each P-H F.C.D on each P-H bond in `P_(2)H_(6)^(2+)`
`=(+2)/6=+0.33`
F.C.D. on each P-H bond in `P_(2)H_(5)^(+)`
`=(+1)/5 =+0.2`
F.C.D. each P-H bond in `PH_(4)^(+)`
`=(+1)/4=+0.25`
Therefore, lowest covalent character of P-H bond is in case of `P_(2)H_(6)^(2+)`