Question

Among the following, the least polarised anion is:

• A. \(NO_3^-\)
• B. \(SO_4^{2-}\)
• C. \(ClO_4^-\)
• D. \(C_2O_4^{2-}\)

Hint:

The weakest conjugate base of the strongest acid is least polarisable.

Answer 1

The Correct Option is C

Higher charge always increases polarisability; rule out SO4(2-), C2O4(2-). Between NO3- and ClO4-, Cl(+7) pulls electron density more tightly than N(+5), giving ClO4- a more compact, tightly bound cloud.

\[\boxed{ClO_4^-}\]