Oxidation-Reduction Reactions Quiz

Questions and Answers

What memory aid is used to summarize the processes of oxidation and reduction?

GREDOL

REDOX

OILRIG (correct)

LEO SAYS GER

What defines the fundamental difference between oxidation and reduction?

Oxidation involves gaining protons, while reduction involves losing protons.

Oxidation is the decrease in oxidation state, reduction is the increase in oxidation state.

Oxidation is the addition of oxygen, reduction is the removal of oxygen.

Oxidation is the loss of electrons, while reduction is the gain of electrons. (correct)

What happens to sulphites when chlorine is added, and why is chlorine classified as an oxidising agent?

Chlorine precipitates with sulphites, preventing oxidation.

Chlorine oxidises sulphite to sulfate by gaining electrons. (correct)

Chlorine forms a gas and does not participate in any redox reaction.

Chlorine decreases sulphites to sodium, it is not an oxidizing agent.

What is observed when dilute HCl is added to a sulphite solution after a white precipitate has formed with BaCl₂?

The white precipitate dissolves. Signup and view all the answers

What color precipitate is formed when NaOH is added to a solution containing Fe²⁺?

Green precipitate Signup and view all the answers

What is a common characteristic of all halogens?

All halogens are oxidising agents with decreasing oxidising ability down the group. Signup and view all the answers

What is the expected observation when chlorine is added to a Fe(II) solution?

Formation of a red-brown precipitate Signup and view all the answers

What describes the role of an oxidising agent in a chemical reaction?

Gains electrons to facilitate oxidation. Signup and view all the answers

Which equation represents the reaction involving Cl₂ and KBr?

Cl₂ + 2KBr → 2KCl + Br₂ Signup and view all the answers

What is the purpose of adding BaCl₂ to a sulphite solution?

To test for sulphites, resulting in a white precipitate. Signup and view all the answers

Study Notes

Oxidation and Reduction

OILRIG is a mnemonic for remembering oxidation and reduction: Oxidation is Loss, Reduction is Gain of electrons.
Oxidation involves the loss of electrons; reduction involves the gain of electrons.

Chemical Tests for Sulphites

BaCl₂ is added to a sulphite solution to test for sulphites; a white precipitate forms if sulphites are present.
Dilute HCl is then added to dissolve the white precipitate formed with BaCl₂; expected observation is that the precipitate dissolves.

Chlorine as an Oxidizing Agent

Chlorine acts as an oxidizing agent because it facilitates oxidation by accepting electrons during reactions.
When chlorine is added to a sulphite solution, it oxidizes sulphite into sulfate.

Testing for Iron Ions

The test for Fe²⁺ ions aims to confirm the absence of Fe³⁺; when 10 drops of NaOH are added to a solution with Fe²⁺, a green precipitate forms.
Chlorine addition to an Fe(II) solution results in a red-brown precipitate due to the formation of Fe(III).

Halogens and Their Properties

All halogens are classified as oxidizing agents, with their oxidizing ability diminishing as one moves down the group in the periodic table.

Role of Chemical Agents

An oxidizing agent is required in a chemical reaction to facilitate oxidation through the acceptance of electrons.
A reducing agent allows reduction to occur by donating electrons.

Key Reactions and Observations

The reaction of Cl₂ with KBr leads to a color change from colorless to orange.
Cl₂ reacts with KI, resulting in a color change from colorless to red/brown.
Br₂ and KI also react, changing from colorless to red/brown.

Description

Test your knowledge on oxidation and reduction reactions, including the definitions and characteristics of these processes. This quiz also covers practical aspects, such as reactions involving sulfur compounds and the role of chlorine as an oxidizing agent.