JEE Advanced 2018 Chemistry question

The surface of copper gets tarnished by the formation of copper oxide. gas was passed to prevent the oxide formation during heating of copper at 1250 K. However, the gas contains 1 mole % of water vapour as impurity. The water vapour oxidises copper as per the reaction given below: is the minimum partial pressure of (in bar) needed to prevent the oxidation at 1250 K. The value of is . (Given: total pressure = 1 bar, (universal gas constant) = 8 J K mol, ln(10) = 2.3. Cu(s) and (s) are mutually immiscible. At 1250 K: ; J mol ; J mol; is the Gibbs energy)