Question

Which of the following polyatomic anion exhibits the valency two?

• A.
  Chlorate ion
• B.
  Oxalate ion
• C.
  Nitride ion
• D.
  Cyanide ion

Answer 1

The correct option is B

Oxalate ion
The formulae of the polyatomic anions along with their valencies are mentioned below.


$\begin{array}{ccc}\text{Anion}& \text{Formula}& \text{Valency}\\ \text{Chlorate}& Cl{O}_3^{-}& \text{1}\\ \text{Oxalate}& C_2{O}_4^{2-}& \text{2}\\ \text{Nitride}& N^{3-}& \text{3}\\ \text{Cyanide}& C{N}^{-}& \text{1}\end{array}$


Hence, the correct answer is option (b).