Page 50 - NCERT Science Class 10 English Medium

n In which test tube did you find that a reaction has occurred?
n On what basis can you say that a reaction has actually taken
place?
n Can you correlate your observations for the Activities 3.9, 3.10
and 3.11?
n Write a balanced chemical equation for the reaction that has taken
place.
n Name the type of reaction.

Reactive metals can displace less
reactive metals from their compounds in
solution or molten form.
We have seen in the previous sections
that all metals are not equally reactive. We
checked the reactivity of various metals
with oxygen, water and acids. But all
metals do not react with these reagents.
So we were not able to put all the metal
samples we had collected in decreasing
order of their reactivity. Displacement
reactions studied in Chapter 1 give better
evidence about the reactivity of metals. It
is simple and easy if metal A displaces
Figure 3.4
Figure 3.4
Figure 3.4
Figure 3.4
Figure 3.4
metal B from its solution, it is more reactive than B. Reaction of metals with
salt solutions
Metal A + Salt solution of B → Salt solution of A + Metal B
Which metal, copper or iron, is more reactive according to your
observations in Activity 3.12?
3.2.5 The Reactivity Series

The reactivity series is a list of metals arranged in the order of their
decreasing activities. After performing displacement experiments
(Activities 1.9 and 3.12), the following series, (Table 3.2) known as the
reactivity or activity series has been developed.
Table 3.2 Activity series : Relative reactivities of metals

K Potassium Most reactive
Na Sodium
Ca Calcium
Mg Magnesium
Al Aluminium
Zn Zinc Reactivity decreases
Fe Iron
Pb Lead
[H] [Hydrogen]
Cu Copper
Hg Mercury
Ag Silver
Au Gold Least reactive

Metals and Non-metals 45

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