Question

Elements of group-$15$ form compounds in $+5$ oxidation state. However, bismuth forms only one well characterised compound in $+5$ oxidation state. The compound is

• A. $Bi_2O_5$
• B. $BiF_5$
• C. $BiCl_5$
• D. $Bi_2S_5$

Answer 1

Answer: (B)

$BiF_5$

Answer 2

The stability of $+5$ oxidation state decreases down the group due to inert pair effect. The only well characterised $Bi(V)$ compound is $BiF_5$ as fluorine being most electronegative element is able to unpair $ns$ electrons.