Order the strongest oxidizing agent to weakest

Question

Four metals represented by the symbols A, B, C, and D, and their ions combine with each other in the following manner:   

B²⁺_(aq) + 2 C_(s)  → 2 C⁺_(aq) + B_(s)

A³⁺_(aq) + C_(s) → no reaction

A³⁺_(aq) + 3 D_(s) → 3 D²⁺_(aq) + 2 A_(s)

The oxidizing agents in order of strongest to weakest below is:

Question 7 options:

	C+(aq)
	A3+(aq)
	B2+(aq)
	D2+(aq)

Answer 1

Note that oxidization is loss of electrons (or negative charge) and an oxidizing agent is an atom that oxidizes another atom and is itself reduced -- it gains electrons (or negative charge).

Think of each reaction (or nonreaction) as being a test to see whether the ion on the reactants side or the ion on the products side is a better oxidizing agent. Think of the two ions as competing for the electrons.

In the first reaction we see B²⁺ react with C, acting as the oxidizing agent, taking electrons away from C and gaining electrons to become the metal B. C⁺ is unable to reverse the reaction as an oxidizing agent, so B²⁺ is a stronger oxidizing agent than C⁺.

In the second reaction, A³⁺ does not react with C. This is as if C+ has reacted with A (in the reverse direction) and now the reaction is complete. This means that C⁺ is a stronger oxidizing agent than A³⁺.

In the third reaction, A³⁺ reacts with D in the same way as the first reaction, so it is a stronger oxidizing agent than D²⁺.

By the way, don't confuse being a strong oxidizing agent with reactivity. Reactivity is measured as how easily an element forms an ion. In fact, the order of reactivity is actually the reverse of the order of strongest oxidizing agents! (D is more reactive than A, etc.)