Question

Describe the reactivity series of metals. Also describe an experiment to decide the order of reactivity of Fe, Cu, and Ag.

Answer 1

The order of intensity of reactivity of metals is known as reactivity series. Metals at the top of the reactivity series are strong reducing agents and hence are easily oxidized. Metals at the top can displace the metals at the bottom in their salt solutions.

Complete Step by step solution:
-Metals form cations through electron loss. Some metals tend to lose electrons easily while some do not.
- The metals that tend to lose electrons are said to be highly reactive while the metals which do not easily lose electrons are said to be less reactive.
-The reactivity series is a series of metals placed in the order of reactivity in the decreasing order. It is used to determine the products of single displacement reactions.
-A single displacement chemical reactions are the chemical reactions in which the element having less reactivity is replaced by another element of high reactivity.
For example, let us see a general reaction,
$A+B-C\to A-C+B$
Where A is less reactive than B.
-The following is the reactivity series of some more common metals in the decreasing order of their reactivity:

METALS	METAL ION	REACTIVITY
K	${{K}^{+}}$	Reacts with water
Na	$N{{a}^{+}}$	Reacts with water
Li	$L{{i}^{+}}$	Reacts with water
Ba	$B{{a}^{2+}}$	Reacts with water
Sr	$S{{r}^{2+}}$	Reacts with water
Ca	$C{{a}^{2+}}$	Reacts with water
Mg	$M{{g}^{2+}}$	Reacts with acids
Al	$A{{l}^{3+}}$	Reacts with acids
Mn	$M{{n}^{2+}}$	Reacts with acids
Zn	$Z{{n}^{2+}}$	Reacts with acids
Cr	$C{{r}^{2+}}$	Reacts with acids
Fe	$F{{e}^{2+}}$	Reacts with acids
Cd	$C{{d}^{2+}}$	Reacts with acids
Co	$C{{o}^{2+}}$	Reacts with acids
Ni	$N{{i}^{2+}}$	Reacts with acids
Sn	$S{{n}^{2+}}$	Reacts with acids
Pb	$P{{b}^{2+}}$	Reacts with acids
${{H}_{2}}$	${{H}^{+}}$	Included for comparison
Sb	$S{{b}^{2+}}$	Highly unreactive
Bi	$B{{i}^{2+}}$	Highly unreactive
Cu	$C{{u}^{2+}}$	Highly unreactive
Hg	$H{{g}^{2+}}$	Highly unreactive
Ag	$A{{g}^{+}}$	Highly unreactive
Au	$A{{u}^{3+}}$	Highly unreactive
Pt	$P{{t}^{+}}$	Highly unreactive

-The following experiment can be carried out for determining the activity series of Fe, Cu, and Ag metals-
(i) Take three test tubes and label them as A, B, and C.
(ii) Add 0.1 gm of ferrous sulfate ($FeS{{O}_{4}}.7{{H}_{2}}O$ ) in the test tube A.
(iii) Add 0.1 gm of copper sulfate ($CuS{{O}_{4}}.5{{H}_{2}}O$ ) in the test tube B.
(iv) Add 0.1 gm of silver nitrate ($AgN{{O}_{3}}$ ) in the test tube C.
(v) Add 10 mL of distilled water in all three test tubes.
(vi) Add zinc metal in the test tube A, iron nail in the test tube B, and copper wire in the test tube C.
-The following observation was made after 30 min-
(i) In test-tube A, the color of ferrous sulfate solution changes from light green to colorless and the zinc metal shows the color of iron metal.
(ii) In test-tube B, the color of copper sulfate changes from dark blue to light blue, and the iron nail shows brown color due to the deposition of copper metal.
(iii) In test-tube C, the color the silver nitrate changes from colorless to light, and the shining white color silver is deposited on copper wire.
Thus we can conclude that-
(i) Zn is more reactive than Fe because Fe is displaced from the ferrous sulfate solution by Zn. ($Zn>Fe$ )
(ii) Cu is more reactive than Ag because Ag is displaced from the copper sulfate solution by Fe. ($Fe>Cu$).
(iii) Cu is more reactive than Ag because Ag is displaced from the silver nitrate solution by Cu. ($Cu>Ag$ ).

Note: Metals as chemical elements, comprises 25% of the earth’s crust. Metals have properties as shiny, lustrous, malleable, ductile, and good conductors of heat and electricity.