Question

Which of the following species is not a pseudohalide?

• A. $CN{O}^{-}$
• B. $RCO{O}^{-}$
• C. $OC{N}^{-}$
• D. $N_3^{-}$

Answer 1

The correct option is B $RCO{O}^{-}$

A psuedohalogen contains two or more atoms out of which at least one is N atom.
$RCO{O}^{-}$ is not a psuedohalogen.
Whereas $CN{O}^{-},OC{N}^{-}and{N}_3^{-}$ are psuedohalogens.