Electrolysis

Molten lead(II) bromide is able to conduct electricity due to the presence of

• free atoms
• molten lead
• mobile ions
• bromine gas

In a simple cell, electrical energy is produced as a result of __________.

• a more reactive metal releasing electrons
• a less reactive metal releasing electrons
• ionic bonds being broken
• positive and negative ions coming together

Which of the following pairs of metals will produce the greatest voltage in a simple cell?

• Iron and copper
• Zinc and copper
• Calcium and magnesium
• Lead and copper

Different combinations of metals produce different voltage because ​ ​ (a)   the two metals are in the reactivity series, the ​ (b)   the voltage produced in the cell. The voltage produced by iron and copper will be ​ (c)   than that of copper and zinc.

• further apart
• greater
• smaller
• larger
• closer together

Label the anode and cathode

The diagram shows the apparatus that a student used to electrolyse aqueous concentrated copper(II) chloride solution. Match the correct products to their respective electrodes.

Negative electrode ​ (a)  

Positive electrode ​ ​ ​ (b)  

• copper
• chlorine

The apparatus used for electrolysis is shown.

Which statement is correct?

• Copper forms at the anode in some electrolysis reactions.

• Hydrogen forms at the cathode in some electrolysis reactions.

• Oxygen forms at the cathode in some electrolysis reactions.

• The negative electrode is called the anode.

A student wishes to electroplate an object with copper.

Which row is correct?

• A

• B

• C

• D

Answer explanation

At the cathode copper ions are discharged to form a layer of copper

Three different compounds are electrolysed.

Which one gives a yellow green gas at the anode?

• 1

• 2

• 3

Answer explanation

Negative electrode attracts cations -

Expt 1 - H+ and Na+

Expt 2 - H+ and Cu2+

Expt 3 - Ca2+ only

In electrolysis, electrons flow from the ​​ (a)   terminal to the ​ ​ (b)  

For simple cell, the electrons flow from the ​ (c)   ​​ also known as the ​negative terminal to the ​ positive terminal

• positive
• negative
• more reactive metal electrode