Question

A, B, C are three elements that undergo chemical reactions according to the following equations:

${\mathrm{A}}_2{\mathrm{O}}_3+2\mathrm{B}\to {\mathrm{B}}_2{\mathrm{O}}_3+2\mathrm{A}$

$3{\mathrm{CSO}}_4+2\mathrm{B}\to {\mathrm{B}}_2{\left({\mathrm{SO}}_4\right)}_3+3\mathrm{C}$

$3\mathrm{CO}+2\mathrm{A}\to {\mathrm{A}}_2{\mathrm{O}}_3+3\mathrm{C}$

Now answer the following questions:

Arrange these elements in the order of reactivity series.

Answer 1

1. Reactivity series

The vertical positioning of metals in the decreasing order of their reactivities is called the reactivity series of metals.

1. The most reactive metal is written at the top of the reactivity series.
2. The least reactive metal is written at the bottom of the reactivity series.

2. Reactivity of A, B and C

Three displacement reactions are given in which a more reactive metal displaces a less reactive metal from its solution.

In the first reaction, metal B displaces metal A from its oxide and in the second reaction metal, C is displaced by metal B from its salt solution. Metal B can displace both metal A and C from its solution. In the third reaction, metal A displaces metal C from its oxide and therefore, metal A is more reactive than C.

The most reactive element is B as it displaces both elements A and C from their compounds. Element C is the least reactive as it gets displaced in the second and third reactions by B and A. Hence, the order of the reactivity series is:

B > A > C