5.5 Changes At The Electrodes

Question 1

What is gaining electrons in electrolysis called?

Answer 1

Reduction, because the positive ions have been reduced to atoms

Question 2

Ions with a 1+ charge gain one electron. How many electrons would a 2+ ion gain?

Answer 2

2

Question 3

What happens at the positive electrode?

Answer 3

Negative ions lose electrons to become neutral atoms

Question 4

What is oxidisation?

Answer 4

When negative ions give their electrons to the positive electrode to become neutral atoms

Question 5

What do some non metals form at the positive electrode?

Answer 5

Molecules, like Br2

Question 6

Complete the half equation for the formation of chlorine at a positive electrode 2Cl-….

Answer 6

2Cl- –> Cl2 + 2e-

Question 7

What ions does water contain?

Answer 7

Hydrogen (+) and hydroxide (-) ions

Question 8

What happens at the negative electrode when water is electrolysed? And under what conditions?

Answer 8

Hydrogen may be produced only if the other positive ions in the solution are those of a metal more reactive than hydrogen

Question 9

What happens at the positive electrode when water is electrolysed? And under what conditions?

Answer 9

Oxygen is produced only of the solution doesn’t contain a reasonably high concentration of a halide ion, otherwise a halogen would be produced

Question 10

What happens at the negative electrode?

Answer 10

The positively charged ions gain electrons to become neutral atoms