Page 100 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

In the fourth test tube, pour some dilute hydrochloric acid/
vinegar to immerse half of the nail.
Observe the changes that occur to the iron nails after one week.

• Which test tubes had their nails rusted?
• Which test tubes had the maximum amount of rust in the
iron nails kept in them?
• What are the factors which favour the corrosion of an iron
article kept exposed to atmosphere?

• Which of the nails did not rust? What could be the reason?
Iron gets rusted when it enters into a chemical reaction with the
oxygen and moisture present in the atmosphere.

• Why do you think the iron window bars in houses close to
the sea shore corrode faster?
• Metals like sodium and potassium are stored in kerosene.
Why?
Iron and a number of other metals react with different
components of air and form new products. This process is known
as corrosion of metals.
Are there metals which are resistant to corrosion? Which are
they? What are their uses? Prepare a note on this.

What possible steps can be adopted to prevent the rusting of
iron?

Significant learning outcomes

The learner can

• identify the physical properties of metals and use them in
daily life.
• produce hydrogen gas by the reaction between metals and
acids.

• explain why metals lose their shining appearance.
• suggest different methods to prevent the corrosion of iron.

Basic Science VIII 99