What is an activity series? How does it help in the extraction of metals?

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To understand the way in which the metal that are very close in properties to each other react and to obtain their order of reactivity we study their reactions with cold water, steam, dilute and strong acids and based upon their reactivity order in these reactions we make our activity series.

Arrangement of the metals in decreasing order of their reactivity is known as the activity series.

Use of activity series in the extraction of metals:

i) The method is used for a particular metal for the reduction of its of its ore to the metal depends on the position of the metal in the activity series.

ii) The metals at the middle of the activity series can be extracted by any of the following methods -

a. Reduction of metal oxide with carbon.

b. Reduction of oxide ores with CO(Carbon monoxide).

c. Self reduction of sulphide ores.

d. Reduction of ores with more reactive metals (thermite process).

iii) The metals which are present at the bottom of the activity series which are less reactive can be extracted by heating alone because these elements are often found in a free state in nature.