chapter 5 electrochemistry class 12 chemistry textbook solution

4. Answer the following :

xiii. Which of the following species are reducing agents? Arrange them in order of increasing strength under standard state conditions. The standard potentials are given in parenthesis.
K (-2.93V), Br2(1.09V), Mg(-2.36V),
Ce3⊕(1.61V), Ti2⊕(-0.37V), Ag⊕(0.8
V), Ni (-0.23V).


  • The substances on the right-hand side of the half-reactions act as reducing agents. Therefore, reducing agents are K, Mg, Ti2+, Ni.
  • The strength of reducing agents increases as their E° values decrease. In ascending order of strength, the reducing agents can be listed as follows:

Ni (E° = -0.23 V) < Ti2+ (E° = -0.37 V) < Mg (E° = -2.36 V) < K (E° = -2.93 V)

chapter 5 elctrochemistry textbook solution page 118