For a cell \( 2M(s) + O_2(g) + 4H^+ \rightarrow 2M^{2+}(aq) + 2H_2O(l) \), the \( E^\circ_{\text{cell}} = +1.67\,V \). When \( [M^{2+}] = 1.0 \times 10^{-3} \, M \) and \( p(O_2) = 0.1 \, atm \), the EMF of the cell becomes \( +1.57 \, V \). Calculate the pH of the electrochemical cell.