C2 - Salt

Question 1

How is salt extracted in Britain?

Answer 1

Salt is extracted from underground deposits left millions of years ago when ancient seas evaporated.

Question 2

What is rock salt?

Answer 2

Rock salt is a mixture of salt and impurities, it is drilled blasted and dug out and brought to the surface using machinery.

Question 3

Describe the process of solution mining.

Answer 3

Pump hot water underground, dissolving the salt. The salt solution is forced to the surface by the pressure of the water.

Question 4

Why is it important to fill in the holes in the ground after mining?

Answer 4

It is important to fill in the hole sin the ground, because if not the land could collapse and slide into the holes, this is called subsidence.

Question 5

What are some uses of salt?

Answer 5

Rock salt can be used in its raw state to stop ice forming no roads.
The salt can be used to enhance or preserve the flavour in food.
The salt can be used for making chemicals, it is usually electrolysed using the chlor-alkali process.

Question 6

What is concentrated brine?

Answer 6

Concentrated Brine is sodium chloride solution.

Question 7

What are the three useful products given off from the electrolysis of concentrated brine.

Answer 7

The three useful products are:
Hydrogen Gas is given off at the cathode
Chlorine Gas is given off at the anode
Sodium hydroxide is formed from the ions left in the solution

Question 8

What are the uses of the three products formed:

Answer 8

Hydrogen gas is used to make ammonia and margarine
The Chlorine is used to disinfect water, to make plastics, solvents or hydrochloric acid.
Sodium Hydroxide is used to make soap or can be reacted with chlorine to make household bleach.