At 298 K the standard reduction potentials for the following half reactions are given asThe strongest reducing agent is

Right hand species readily undergoes oxidation and is strong reducing agent.Left hand species readily undergo reduction and is strong oxidising agentAmong the given SRP values Zn  electrode is having  lowest value. The right hand species  Zn is readily undergoing oxidation and is strong reducing agent.Order is Among the given SRP values Fe electrode is having highest value. The left hand species Fe+3 readily undergoes reduction and is strong oxidizing agent.Order isFe+3 >H+ >Cr+3 >Zn+2