262. Calculate the pH of the following half reactions: Pt. H₂ (1 atom) / HCl, E = 0.25 V.

Calculate the molar conductivity at infinite dilution of acetic acid from the following data:
Λ^∞_m (HCl) = 426 ohm^–1 cm² mol^–1, Λ^∞_m CH₃COONa = 91 ohm^–1 cm² mol^–1 and Λ^∞_m(NaCl) = 126 ohm^–1 cm² mol^–1.

Consider the cell Zn/Zn²⁺ (aq) (1.0 M) || Cu²⁺ (aq) (0.1 M) | Cu The standard reaction potentials are + 0.35 V for 2e^– + Cu²⁺ (aq) → Cu and – 0.763 V for 2e^– + Zn²⁺ (aq) → Zn
(i) Write down the cell reaction.
(ii) Calculate the emf of the cell.
(iii) Is the cell reaction spontaneous or not?

The standard reduction potential of the reaction at 25°C
2H₂O + 2e^– H₂(g) + 2OH^– is – 0.8277 V
Calculate equilibrium constant for the reaction
$2{\mathrm{H}}_2\mathrm{O}\leftrightharpoons {\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{OH}}^{-}$ at $25°\mathrm{C}.$