Question

Which of the following statements about the reaction is/are correct?

$2Au{Cl}_4^{\ominus }+3Zn⟶2Au+3{Zn}^{2+}+8{Cl}^{\ominus }$

• A. $Au{Cl}_4^{\ominus }$ is reduced to $Au$
• B. $Zn$ is oxidised to ${Zn}^{2+}$
• C. ${Cl}^{\ominus }$ is a spectator ion
• D. It is an intermolecular redox reaction

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A $Au{Cl}_4^{\ominus }$ is reduced to $Au$
B $Zn$ is oxidised to ${Zn}^{2+}$
C ${Cl}^{\ominus }$ is a spectator ion
D It is an intermolecular redox reaction

As in ${AuC{l}_4}^{-}$, Au has $+3$ oxidation state which changes to 0 (zero). Hence, it is getting reduced.

Zn is in zero oxidation state which changes to $+2$ in $Z{n}^{2+}$. Hence, it is getting oxidized.

A spectator ion is an ion that exists in the same form on both the reactant and product sides of a chemical reaction.
It means that the oxidation state of $C{l}^{-}$ ion does not change as it remains the same, i.e. -1.

${AuC{l}_4}^{-}$ and $Zn$ is undergoing redox reaction in which $Au$ is reduced and $Zn$ is oxidised. Hence, it is an intermolecular redox reaction.