For an electrochemical cell

Sn(s) | Sn²⁺ (aq,1M)||Pb²⁺ (aq,1M)|Pb(s)

the ratio $${{\left[ {S{n^{2 + }}} \right]} \over {\left[ {P{b^{2 + }}} \right]}}$$ when this cell attains equilibrium is _________.

(Given $$E_{S{n^{2 + }}|Sn}^0 = - 0.14V$$,

$$E_{P{b^{2 + }}|Pb}^0 = - 0.13V$$, $${{2.303RT} \over F} = 0.06$$)

What would be the electrode potential for the given half cell reaction at pH = 5? ______.

2H₂O $$ \to $$ O₂ + 4H^{$$ \oplus $$} + 4e^– ; $$E_{red}^0$$ = 1.23 V

(R = 8.314 J mol^–1 K^–1 ; Temp = 298 k;

oxygen under std. atm. pressure of 1 bar)