Redox Equations Quiz

What is the first step in balancing a redox equation using the half-reaction method?

• Combine the half-reactions.

• Balance the elements other than oxygen and hydrogen.

• Identify the oxidation and reduction half-reactions.

• Balance the charge by adding electrons.

Answer explanation

The first step in balancing a redox equation using the half-reaction method is to identify the oxidation and reduction half-reactions.

In the oxidation number method of balancing redox equations, what is the correct sequence of steps?

• Assign oxidation numbers, balance the atoms, balance the charge.

• Balance the atoms, assign oxidation numbers, balance the charge.

• Assign oxidation numbers, balance the charge, balance the atoms.

• Balance the charge, assign oxidation numbers, balance the atoms.

Answer explanation

The correct sequence of steps in the oxidation number method of balancing redox equations is to first assign oxidation numbers, then balance the atoms, and finally balance the charge.

Which of the following is balanced correctly in basic solution?

Answer explanation

The correct choice is the balanced equation: Cl2 + OH- -> Cl- + ClO3- + H2O, which is balanced correctly in basic solution.

What is the role of the substance that gets reduced in a redox reaction?

• It acts as a reducing agent.

• It acts as an oxidizing agent.

• It donates electrons.

• It accepts protons.

Answer explanation

In a redox reaction, the substance that gets reduced acts as an oxidizing agent by accepting electrons from the substance that gets oxidized.

Answer explanation

The reducing agent is the species that gets oxidized. In this reaction, Sn^{2+} is oxidized to Sn^{4+}, making it the reducing agent.

When balancing a redox reaction in an acidic solution, what is added to balance hydrogen atoms?

Answer explanation

In an acidic solution, H⁺ ions are added to balance hydrogen atoms in a redox reaction.

Answer explanation

In the given reaction, the species that causes another species to be oxidized is the oxidizing agent. Here, Cr2O7^2- oxidizes Fe^2+ to Fe^3+, making Cr2O7^2- the oxidizing agent.

Tags

NGSS.HS-PS1-2

What is added to both sides of a redox equation to balance it in basic solutions?

Answer explanation

In basic solutions, ηH^- ions are added to both sides of a redox equation to balance it by neutralizing the ηH^+ ions.

Which of the following statements is true regarding the balancing of redox reactions?

• The number of electrons lost in the oxidation half-reaction must equal the number of electrons gained in the reduction half-reaction.

• Electrons are added to the side of the half-reaction that is being oxidized in the final step.

Answer explanation

The correct statement is that the number of electrons lost in the oxidation half-reaction must equal the number of electrons gained in the reduction half-reaction.

Provide an example of balancing a redox equation in an acidic solution.

• 2Na(s) + 2H2O(l) -> 2NaOH(aq) + H2(g)

• 2H+(aq) + 2e- -> H2(g)

• Fe(s) + 2HCl(aq) -> FeCl2(aq) + H2(g)

• 2H2O(l) -> 2H2(g) + O2(g)