C2h

Question 1

How is salt extracted from the ground?

Answer 1

• drilled, blasted and dug out and brought to the surface by machinery
• solution mining

Question 2

Why is it important to fill holes after mining?

Answer 2

-land could collapse and slide into holes (subsidence)

Question 3

What are the useful products of the electrolysis of brine?

Answer 3

• hydrogen gas
• chlorine gas
• sodium hydroxide

Question 4

How is sodium chloride solution (concentrated brine) electrolysed?

Answer 4

-electrodes made of inert materials, so they don’t react with the electrolyte or products
1-brine enters
2-at cathode two hydrogen ions accept one electron each to become on hydrogen molecule
3-at anode two chloride ions lose one electron to become one chlorine molecule

Question 5

What are the uses of the products of the electrolysis of brine?

Answer 5

• hydrogen gas:make ammonia and margarine
• chlorine: disinfect water, make plastic and solvents and hydrochloric acid
• sodium hydroxide:used to make soap, can be reacted with chlorine to make household bleach

Question 6

What is solution mining?

Answer 6

• pumping hot water underground

- salt dissolves and salt solution is forced to surface by pressure of the water

Question 7

Why is the chloro-alkali industry important for the economy?

Answer 7

• may uses of the products from reaction

- lots of new products can be made and lots of jobs created