Redox Reactions

Choose all the statements which contain correct definitions of reduction

• the removal of oxygen

• the removal of hydrogen

• the removal of electrons

• the decrease in oxidation state

Which one of the following conversions is an example of reduction?

• Copper (II) oxide to copper (II) sulfate

• Copper (II) oxide to copper

• Hydrochloric acid to chlorine

• Lead (II) nitrate to lead (II) chloride

The ionic equation shows the reaction between zinc (Zn) and hydrochloric acid.

Zn + 2H⁺ -> Zn²⁺ + H₂

What change takes place in the zinc?

• It gains electrons

• Its oxidation state increases

• It is reduced

• It gains hydrogen

When a gas changes iron (III) oxide to iron (II) oxide, it shows that the gas is

• a reducing agent

• an oxidizing agent

• a combustible gas

• a diffusible gas

Choose all the statements which are correct for an oxidising agent.

• removes hydrogen

• gains oxygen

• is reduced at the end of the reaction

• accepts electrons

In the reaction, Fe₂O₃(s) + 3CO(g) → 2Fe(l) + 3CO₂(g)

• carbon monoxide is reduced

• carbon monoxide is the oxidising agent

• iron(III) oxide is oxidised

• iron(III) oxide is the oxidising agent

Name the oxidising agent in the following reaction:

nitrogen + hydrogen -> ammonia

• nitrogen

• hydrogen

• ammonia

• A

• B

• C

• D

State the reducing agent in this reaction.

Cu + 4HNO₃ -> Cu(NO₃)₂ + 2H₂O + 2NO₂

• Cu

• HNO₃

• Cu(NO₃)₂

• NO₂

Check all the equations whereby the underlined substances has been oxidized.

• carbon dioxide + carbon -> carbon monoxide

• iron (II) oxide + aluminium -> aluminium oxide + iron

• copper (II) oxide + ammonia -> copper + nitrogen + water

• hydrogen + oxygen -> water