Chapter 18, Problem 4STP

Interpretation Introduction

Interpretation:From the given reactionoxidizing and reducing agent needs to be identified.

Concept introduction:Oxidizing agent gains one or more electrons from another reactant. Due to this reason oxidizing agent gets reduced and oxidizes other species. Reducing agent donates electrons to another reactant.

Answer to Problem 4STP

Correct Answer: Option A. ${\text{Cl}}_{\text{2}}=\text{oxidizing}\text{agent,}$ NaBr = reducing agent

Explanation of Solution

Reason for correct option:

Given reaction is as follows:

  ${\text{Cl}}_{\text{2}}\left(g\right)+2\text{NaBr}\left(s\right)\to {\text{Br}}_{\text{2}}\left(g\right)+\text{2NaCl}\left(s\right)$

In this reaction oxidation state of chlorinedecreases from 0 to -1 and oxidation state of bromine increases from -1 to 0. Thus, in the given reaction,chlorine acts as oxidizing agent and bromine (NaBr) acts as reducing agent.

Conclusion

Reason for incorrect option:

B. NaBr = oxidizing agent, ${\text{Cl}}_{\text{2}}=\text{reducing}\text{agent}$

NaBr is a reducing agentbecause oxidation state of Br increases from -1 to 0 in the reaction and ${\text{Cl}}_{\text{2}}$ isan oxidizing agent because oxidation state of Cl decreases from 0 to -1.

C. ${\text{Cl}}_{\text{2}}=\text{oxidizing}\text{agent,}$${\text{Br}}_{\text{2}}=\text{reducing}\text{agent}$

  ${\text{Cl}}_{\text{2}}$ is an oxidizing agent because oxidation state of Cl decreases from 0 to -1 but Br₂is not a reducing agent as it is getting reduced to Br- or it is not getting oxidized.

  ${\text{Cl}}_{\text{2}}$ isan oxidizing agentand NaBr is not a reducing agent.

D. NaCl=oxidizing agent, NaBr = reducing agent

NaBr = reducing agent is a reducing agent but NaCl is not an oxidizing agent as Cl- in NaCl ca not further reduced.