2.12.2 Group 2 Ions

Question 1

What are the two factors that affect solubility?

Answer 1

• The volume of the solvent

- The temperature of the solvent

Question 2

What is the trend in solubility down the group 2 hydroxides

Answer 2

The solubility increases down the group

Question 3

What is magnesium hydroxide used as?

Answer 3

It’s used as an antacid, to relieve the symptoms of indigestion and heartburn by neutralising the acid

Question 4

What is a use of calcium hydroxide?

Answer 4

Farmers use limestone to control the acidity of their soil.

Question 5

How is limestone made?

Answer 5

Limestone is made from calcium carbonate, which decomposes to form calcium hydroxide
CaCO3(s) –> CaO(s) + CO2(g)
CaO(s) + H2O(l) –> Ca(OH)2(s)

Question 6

What is the trend in solubility of the group 2 sulfates?

Answer 6

The solubility of the group 2 sulfates decreases as you go down the group

Question 7

What is a use of barium sulfate?

Answer 7

Barium compounds are toxic, but barium sulfate is very insoluble, so it can be digested so that x-rays can be taken of the digestive system. This is called barium meal.

Question 8

What is the test for sulfates?

Answer 8

A white precipitate of barium sulfate forms when barium chloride solution is added to a solution containing sulfate ions.
It is important to acidify the test sample using hydrochloric or nitric acid