(a) What is meant by the reactivity series of metals? Arrange the following metals in increasing order of their reactivities towards water: Zinc, Iron, Magnesium, Sodium. (b) Hydrogen is not a metal but still, it has been assigned a place in the reactivity series of metals. Why?

Solution:

(a) A reactivity series is a vertical column of items arranged in decreasing order of their reactivities.

Increasing order of reactivity : Iron< Zinc< Magnesium< Sodium

(b) Although hydrogen is not a metal, it is included in the metal reactivity series because, like metals, it loses electrons and creates positive ions.