Q.

Based on the data given below:

ECr2O72-/Cr3+=1.33 V     ECl2/Cl-=1.36 V

EMnO4-/Mn2+=1.51 V     ECr3+/Cr=-0.74 V

The strongest reducing agent is:                               [2025]

1 Mn2+  
2 Cl-  
3 MnO4-  
4 Cr  

Ans.

(4)

Strongest reducing agent is the specie which has highest tendency to get oxidized i.e. the one with highest oxidation potential.

Reduction potential Oxidation potential
ECr2O72-/Cr3+=1.33 V ECr3+/Cr2O72-=-1.33 V
ECl2/Cl-=1.36 V ECl-/Cl2=-1.36 V
EMnO4-/Mn2+=1.51 V EMn2+/MnO4-=-1.51 V
ECr3+/Cr=-0.74 V ECr/Cr3+=0.74 V