Electrolysis

Question 1

What does electrolysis mean?

Answer 1

Splitting up electricity.

Question 2

What happens if you pass an electric current through an ionic substance that’s molten or in a solution?

Answer 2

It breaks down the elements its made of.

Question 3

What does electrolysis require?

Answer 3

Liquid - To conduct the electricity. (An electrolyte)

Question 4

What do electrolytes contain?

Answer 4

• Free electrons (Usually molten or dissolved iconic substance)

Question 5

Free electrons…

Answer 5

Conduct electricity.

Question 6

What is needed for an electrical circuit to be complete?

Answer 6

• Flow of electrons

Question 7

What happens to ions as they gain or lose electrons at the positive electrode

Answer 7

They are given to other ions at the negative electrode. As ions lose or gain electrons they become atoms or molecules are released

Question 8

Oxidation is…

Answer 8

LOSS of electrons

Question 9

Reduction is…

Answer 9

GAIN of electrons

Question 10

What a salt is molten it…

Answer 10

Will conduct electricity.

Question 11

The electrolysis of molten lead bromide: where is the lead produced?

Answer 11

At the negative electrode.

Question 12

In the electrolysis of molten lead bromide what are the +ve ions attracted too?

Answer 12

The -ve electrode

They GAIN electrons here

Question 13

In the electrolysis of molten lead bromide what are the -ve ions attracted too?

Answer 13

The +ve ions

They LOSE electrons here

Question 14

The electrolysis of molten lead bromide: where is the Bromine produced?

Answer 14

At the positive electrode.

Question 15

In the electrolysis of molten lead bromide what happens at the -ve electrode?

Answer 15

One lead ions accepts two electrons to become one lead atom.

Question 16

In the electrolysis of molten lead bromide what happens at the +ve electrode?

Answer 16

Two Bromide ions lose one electron each and become one bromide molecule.

Question 17

What does radioactivity affect?

Answer 17

The products formed by electrolysis

Question 18

Sometimes there are more than …… ions in the electrolyte

Answer 18

Two free

Question 19

If a salt is dissolved in water what ions will be present?

Answer 19

H+ and OH-

Question 20

What ions are present at the negative electrode

Answer 20

H+

The metal ions will stay in solution if the metal is more reactive than hydrogen

Question 21

Hydrogen will be produced unless…

Answer 21

The metal is less reactive than it

Question 22

What ions are present at the positive electrode

Answer 22

OH- and halide ions (CL-, Br-, I-)
If halide ions are present -> molecules of chlorine, bromine or iodine will form
If not -> Oxygen is formed

Question 23

In the electrolysis of Sodium chloride solution what happens at the negative electrode?

Answer 23

Two hydrogen ions accept two electrons to become one hydrogen molecule.

Question 24

In the electrolysis of Sodium chloride solution what happens at the positive electrode?

Answer 24

Two chloride (Cl-) ions lose their electrons and become one chlorine molecule.

Question 25

In the electrolysis of Sodium chloride solution what happens to the sodium ions?

Answer 25

• Stay in solution (more reactive than hydrogen)
• Hydroxide ions from water are also left behind
• Sodium hydroxide (NaOH) is left in the solution

Question 26

When sodium chloride is dissolved in water and electrolysed what does it produce?

Answer 26

3 Useful products:

• Hydrogen
• Chlorine
• Sodium hydroxide

Question 27

In the electrolysis of Sodium chloride solution what is produced at the -ve electrode?

Answer 27

Hydrogen (H+)

Question 28

In the electrolysis of Sodium chloride solution what is produced at the +ve electrode?

Answer 28

Chlorine (Cl-)

Question 29

Negative electrode (half equation)

Answer 29

2H+ + 2e- -> H2 (small 2)

Question 30

Positive electrode (hald equation)

Answer 30

2Cl- -> Cl2 (small 2) + 2e- OR 2Cl- - 2e- -> Cl2 (small 2)

Question 31

Name the uses of chlorine in industry

Answer 31

Production of;

• Bleach
• Plastic

Question 32

Name the uses of Sodium hydroxide in industry

Answer 32

Strong alkali used in;

• Chemical industry
• Soap