Redox reactions (2)

What is a redox reaction?

• A redox reaction is a reaction where two substances are combined without any change in their oxidation states.

• A redox reaction is a process that only involves the formation of new compounds.

• A redox reaction is a chemical reaction involving the transfer of electrons, where one substance is oxidized and another is reduced.

• A redox reaction is a type of reaction that does not involve any electron transfer.

Oxidation is

• the decrease in oxidation state

• the transfer of protons

• the gain of hydrogen

• the loss of electrons

What is reduction?

• gaining oxygen

• gaining electrons

• losing hydrogen

• losing electrons

Identify the oxidizing agent in a redox reaction.

• The substance that acts as a catalyst in the reaction.

• The substance that gains electrons and is reduced.

• The substance that remains unchanged during the reaction.

• The substance that loses electrons and is oxidized.

Identify the reducing agent in a redox reaction.

• The reducing agent is the substance that remains unchanged.

• The reducing agent is the substance that accepts electrons.

• The reducing agent is the substance that donates electrons.

• The reducing agent is the substance that increases oxidation state.

What is the role of electrons in redox reactions?

• Electrons are solely responsible for heat generation.

• Electrons are not involved in chemical reactions.

• Electrons are only involved in ionic bonding.

• Electrons are transferred between reactants

Choose all the processes that are redox reactions.

• Fractional distillation of liquid mixtures

• Sublimation of iodine crystals

• Rusting of iron, forming rust, which is hydrated iron(III) oxide

• Melting of ice

For redox reactions, half equations show

• electrons loss and gain for each element, and together they show the complete redox reaction.

• show transfer of electrons without any change in oxidation states.

• spectator ions and how they lose and gain electrons.

• show the complete reaction without needing to consider oxidation or reduction.

Displacement of copper from copper(II) nitrate solution, using zinc ribbon.
Which option describes the correct electron transfer?

• Zinc loses electrons, Cu²⁺ gain electrons

• Cu²⁺ loses electrons, zinc gains electrions.

• There is no electron transfer

• Nitrate lose electrons, zinc gains electrons.

Choose all that show the underlined substance in the equation being oxidised.

• C + O₂ → CO₂

• 2CO + O₂ → 2CO₂

• S + O₂ → SO₂

• H₂O → O₂ + H₂