Given the standard electrode potentials:
$K^{+} / K = -2.93 \, V$,$Ag^{+} / Ag = 0.80 \, V$
$Hg^{2+} / Hg = 0.79 \, V$
$Mg^{2+} / Mg = -2.37 \, V$,$Cr^{3+} / Cr = -0.74 \, V$
Arrange these metals in their increasing order of reducing power.

(A) The reducing power of a metal is inversely proportional to its standard reduction potential. $A$ lower (more negative) reduction potential indicates a stronger reducing agent.
The given standard reduction potentials are:
$K^{+} / K = -2.93 \, V$
$Mg^{2+} / Mg = -2.37 \, V$
$Cr^{3+} / Cr = -0.74 \, V$
$Hg^{2+} / Hg = 0.79 \, V$
$Ag^{+} / Ag = 0.80 \, V$
Arranging these in increasing order of reduction potential:
$K < Mg < Cr < Hg < Ag$
Therefore,the increasing order of reducing power is:
$Ag < Hg < Cr < Mg < K$