Arrange the following ions in the order of decreasing X-O bond lenght where X is the central atom. (a) ClO₄ ^-, SO₄ ^2-, PO₄ ^3-, SiO₄ ^4-.

(b) SiO₄ ^4-, PO₄ ^3-, SO₄ ^2-, ClO₄ ^-.

(c) SiO₄ ^4-, PO₄ ^3-, ClO₄ ^-, SO₄ ^2-.

(d) SiO₄ ^2-, SO₄ ^2-, PO₄ ^3-, ClO₄ ^-.

(e) SO₄ ^2-, PO₄ ^3-, ClO₄ ^-, SiO₄ ^4-,

Dear Student,

The correct order is (b).
The bond length of single bond is greater than double bond, and double bond is greater than triple bond.
SiO_​4^4- has all 4 single bonds which makes its bond length longest.

PO₄^3- contains one double bond.

 SO₄^2- contains two double bonds
 
ClO₄^- contains 3 double bond

Since bond order is inversely proportional to bond length, so the order is (b)