Aluminium is higher than iron in the reactivity series. To see if this was true, Ayesha took similar sized pieces of aluminium and iron in test tubes. She added the same volume of dilute hydrochloric acid in each. She noticed that: Initially there was a more vigorous evolution of gas from the test tube having iron. After a couple of minutes, aluminium starts reacting much faster than iron and the evolution of gas is much more vigorous. She was confused. Can you explain to her why this happened?

Iron reacts with dilute hydrochloric acid to form ferrous chloride and hydrogen gas. Fe s + 2 HCl aq → FeCl 2 aq + H 2 g Aluminium when exposed to the air, forms a layer of aluminium oxide . When dilute hydrochloric acid is added to it, first, the oxide gets removed. The aluminium metal then reacts with the acid to form aluminium chloride. Hence, the vigorous reaction and evolution of gas were observed a couple of minutes after iron. Al 2 O 3 s + 6 HCl aq → 2 AlCl 3 aq + 3 H 2 O l

E M B I B E

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 1

EASY

8th CBSE

IMPORTANT

Earn 100

Silver is the best conduct of electricity. Can you say why electric wires are not made up of silver?

Important Questions on Metals and Non-Metals

EASY

8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 2

Why are bells made from metals and not from wood?

EASY

8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 3

Suppose copper was high up in the reactivity series. Would it still have been such a useful metal? Give the reason.

EASY

8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 4

It has been noticed that silverware becomes black faster today than it did fifty years ago. What can be the reason for this?

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8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 5

Aluminium is above iron in the reactivity series. However, its reaction with oxygen and water seems to indicate that it is less reactive than iron. Explain.

EASY

8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 6

If you are an engineer constructing a multi-storey building, which alloy would you be extensively using and why?

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8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>EXERCISES>Q 7

A doctor diagnosed a patient with iron deficiency, and gave him tablets containing iron. But the tablets were not hard and did not look like iron at all. What do you think the tablets contained?

HARD

8th CBSE

IMPORTANT

Living Science 8>Chapter 4 - Metals and Non-Metals>BE A SCIENTIST

Aluminium is higher than iron in the reactivity series. To see if this was true, Ayesha took similar sized pieces of aluminium and iron in test tubes. She added the same volume of dilute hydrochloric acid in each. She noticed that:

Initially there was a more vigorous evolution of gas from the test tube having iron.
After a couple of minutes, aluminium starts reacting much faster than iron and the evolution of gas is much more vigorous.

She was confused. Can you explain to her why this happened?