In a hydrogen – oxygen fuel cell, combustion of hydrogen occurs to :

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?

In a cell that utilises the reaction Zn(s) + 2H⁺ (aq) $$\to$$ Zn2+(aq) + H2(g) addition of H₂SO₄ to cathode compartment, will

Consider the following E^o values

$$E_{F{e^{3 + }}/F{e^{2 + }}}^o$$ = 0.77 V;

$$E_{S{n^{2 + }}/S{n}}^o$$ = -0.14 V

Under standard conditions the potential for the reaction

Sn(s) + 2Fe³⁺(aq) $$\to$$ 2Fe²⁺(aq) + Sn²⁺(aq) is :