Question

Which of the following substances will react more strongly with each other (select the best reducing agent and the best oxidizing agent):

Half-reaction              E^o, V

Fe³⁺ + 3e- --> Fe(s)     0.771

Sn⁴⁺ + 2e- --> Sn(s)    0.154

Pb²⁺ + 2e- --> Pb(s)    -0.126

Sn²⁺ + 2e- --> Sn(s)   -0.136

Question options:

	Fe3+ and Fe(s)
	Fe(s) and Sn2+
	Fe3+ and Sn(s)
	Sn4+ and Sn2+

Answer 1

A negative reduction potential tells us that the ion is harder to reduce (is a worse oxidizing agent) than is the hydrogen ion; this also tells us that the metal is a better reducing agent than is hydrogen gas.

A positive reduction potential tells us that the ion is easier to reduce (is a better oxidizing agent) than is the hydrogen ion; this also tells us that the metal is a worse reducing agent than is hydrogen gas.

Hence Fe+3 is the strongest oxidising agent among the given.

and Sn(s) is the best reducing agent.