Electrolysis

A Lithium ion (Li⁺) has two electrons. What needs to happen to it for it to turn back into an atom?

• Gain one electron

• Lose one electron

• Gain two electrons

• Lose two electrons

An oxide ion (O^2-) has 10 electrons. What needs to change for it to become an atom?

• Gain one electron

• Lose one electron

• Gain two electrons

• Lose two electrons

A liquid, containing free-moving ions, which is broken down by electricity in the process of electrolysis is called the.......

The positive electrode in electrolysis is called the.....

• anode

• cathode

During the electrolysis of Aluminium oxide, aluminium ions move to the negative electrode. Explain why. (2 marks)

A student investigated the electrolysis of zinc chloride. They observed that a silvery metal was produced at the negative electrode and a yellow-green gas was produced at the positive electrode. What happed to the zinc chloride? Name the products at each electrode. (3 marks)

When solid zinc chloride was used there was no reaction. Explain why. (2 marks)

Fill in the correct coefficient for the following half equation:

Al³⁺ + _e^- -> Al

Select the half equations that are showing oxidation.

• Cl₂ + 2e^- -> 2Cl^-

• Fe²⁺ -> Fe³⁺ + e^-

• Mg -> Mg²⁺ + 2e^-

• H^- -> H⁺ + 2e^-

• 2H⁺ + 2e^- -> H₂