The $$E_{{M^{3 + }}/{M^{2 + }}}^o$$ values for Cr, Mn, Fe and Co are – 0.41, +1.57, + 0.77 and +1.97 V respectively. For which one of these metals the change in oxidation state form +2 to +3 is easiest?

For a cell reaction involving a two-electron change, the standard e.m.f. of the cell is found to be 0.295 V at 25^oC. The equilibrium constant of the reaction at 25^oC will be

Standard reduction electrode potentials of three metals A,B&C are respectively +0.5 V, -3.0 V & -1.2 V. The reducing, powers of these metals are

Several blocks of magnesium are fixed to the bottom of a ship to :