1. CHEMISTRY DEPARTMENT WAID ACADEMY Standard Grade Topic 12

2. Which substance, or substances, must be present for a metal to corrode? 1.Water only. 2.Oxygen only. 3.Both water and oxygen. 4.Both water and salt. 20

3. Rusting is the term used to describe the corrosion of which metal? 1.Zinc. 2.Lead. 3.Copper. 4.Iron. 20

4. Which of substances shown below is formed in the first stage of iron rusting ? 1.Fe atoms. 2.Fe 2+ ions 3.Fe 3+ ions 20

5. Which box below shows the two reactions which occur when iron rusts? 1.A. 2.B. 3.C. 4.D. 30

6. Which chemical can be used to show how much rusting has taken place? 1.Universal Indicator. 2.Ferroxyl indicator. 3.Bromine solution. 4.Benedict’s solution 20

7. Steel food cans have a thin layer of tin applied to the outer surface of the steel using electricity. What name is given to this process? 1.Electroplating.. 2.Anodising. 3.Galvanising. 4.Painting. 20

8. Which line two metals which can both protect iron against rusting by being joined to the iron? 1.Copper and zinc 2.Zinc and tin 3.Magnesium and zinc 4.Magnesium and copper 20

9. Anodising thickens the oxide layer on 20 1.Copper 2.Zinc 3.Magnesium 4.Aluminium

10. Which metal is used to protect iron and steel by galvanising? 1.Copper 2.Zinc 3.Magnesium 4.Tin 20

11. When iron rusts the metal 1.loses structural strength. 2.turns from an compound into an element. 3.gets stronger. 4.forms a protective barrier on its surface. 20