Electrolysis of Sodium Chloride Flashcards Preview

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Flashcards in Electrolysis of Sodium Chloride Deck (15)
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1
Q

When common salt ([ ]) is dissolved in water and electrolysed, it produces these useful products - [ ], chlorine and [ ]

A

Sodium chloride
Hydrogen
Sodium hydroxide

2
Q

[ ] is produced at the -ve electrode

A

Hydrogen

3
Q

[ ] is produced at the +ve electrode

A

chlorine

4
Q

[ ] are released from the water

A

H+ ions

5
Q

What happens at the negative electrode?

A

2 hydrogen ions accept 2 electrons to become 1 hydrogen molecule

6
Q

In order to be elctrolysed, sodium chloride is [ ]

A

In solution

7
Q

What happens at the positive electrode?

A

2 chloride ions (Cl-) lose their electrons and become 1 chlorine molecule

8
Q

What happens to all the other ions (not the ones forming molecules at the electrodes)? Why?

A

The sodium ions stay in solution because they’re more reactive than hydrogen
Hydroxide ions from water are also left behind. This means that sodium hydroxide (NaOH) is left in the solution

9
Q

What do half-equations show? What must you make sure of?

A

Show the reactions at the electrodes.

Make sure the number of electrons is the same for both half-equations

10
Q

What is the half-equation of for the electrolysis of sodium chloride at the negative electrode?

A

2H⁺ + 2e⁻ -> H₂

11
Q

What is the half-equation of for the electrolysis of sodium chloride at the positive electrode?

A

2Cl⁻ -> Cl₂ + 2e⁻

OR 2Cl⁻ - 2e⁻ -> Cl₂

12
Q

What is the half-equation of for the electrolysis of molten lead bromide at the negative electrode?

A

Pb²⁺ + 2e⁻ -> Pb

13
Q

What is the half-equation of for the electrolysis of molten lead bromide at the positive electrode?

A

2Br⁻ -> Br₂ + 2e⁻

14
Q

Give an example of what chlorine can be used for

A

Production of bleach and plastics

15
Q

Describe sodium hydroxide (uses)

A

Very strong alkali and is used widely in the chemical industry eg, to make soap