Given the standard electrode potentials,

$straight K to the power of plus divided by straight K space equals negative 2.93 space straight V comma space space space Ag to the power of plus divided by Ag space equals space 0.80 space straight V Hg to the power of 2 plus end exponent divided by Hg space equals space 0.79 space straight V Mg to the power of 2 plus end exponent divided by Mg space equals space minus 2.37 space straight V comma space space space Cr to the power of 3 plus end exponent divided by Cr space equals space minus 0.74 space straight V arrange space these space metals space in space their space increasing space order space of space reducing space power.$

Solution

We know the reducing power of a metal depends on upon its tendency to lose electrons. Thus, lower the reduction potential, more the tendency to get oxidised and thus more will be the reducing power. Hence increasing order of reducing power of metals is,
Ag < Hg < Cr < Mg < K.