Question

The correct order of polarizability is $I^{-},B{r}^{-},C{l}^{-},F^{-}$

• A. $I^{-}>B{r}^{-}>C{l}^{-}>F^{-}$
• B. $I^{-}>B{r}^{-}=C{l}^{-}>F^{-}$
• C. $I^{-}=B{r}^{-}=C{l}^{-}>F^{-}$
• D. $I^{-}=B{r}^{-}=F^{-}<C{l}^{-}$

Answer 1

The correct option is A $I^{-}>B{r}^{-}>C{l}^{-}>F^{-}$

The ability of ion to undergo polarization is called its polarizability. The polarizing power of cation and polarizability of anion are decided on the basis of Fajan rules as given below:
i) The smaller the cation, the higher is its polarizing power.
ii) Cations with pseudo noble gas configuration (ns${}^2$np${}^6$nd${}^{10}$)having relatively high polarizing power than those with noble gas configuration (ns${}^2$np${}^6$).
iii) The larger the size of the anion, the higher is its polarizability.
the order of size of anions are $I^{-}>B{r}^{-}C{l}^{-}>F^{-}$ so same is the polarizibility order.