Chemistry - Electrochemistry Question with Solution | TestHub

The surface of copper gets tarnished by the formation of copper oxide.$N_2$gas was passed to prevent the oxide formation during heating of copper at 1250 K. However, the$N_2$gas contains 1 mole % of water vapour as impurity. The water vapour oxidises copper as per the reaction given below:$2Cu\left(s\right)+ H_{2}O\left(g\right)\to C{u}_{2}O\left(s\right) + H_2\left(g\right)$$P_{H_2}$Is the minimum partial pressure of$H_2$(in bar) needed to prevent the oxidation at 1250 K. The value of$\ln \left(p{H}_2\right)$is ____. (Given: total pressure = 1 bar, R (universal gas constant)$= 8 J K^{-1} mo{l}^{-1},\ln \left(10\right) = 2.3. Cu\left(s\right) and C{u}_{2}O\left(s\right)$are mutually immiscible. At$1250 K: 2Cu\left(s\right)+\frac{1}{2} O_2\left(g\right)\to C{u}_{2}O\left(s\right); ∆G^{⊝} = - \mathrm{78,000} J mo{l}^{-1}$$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to H_{2}O\left(g\right); {∆}^{⊝} = - \mathrm{1,78,000} J mo{l}^{-1}; G$is the Gibbs energy)