[roilaa]

 For the same reaction, the standard Gibbs
energy of reaction at 2000K is +135.2 kJmol−1
. Suppose that
steam at 200 kPa is passed through a furnace tube at that
temperature. Calculate the mole fraction of O2 present in the
output gas stream.

i cant find the right result

[Borek]

No way to help without knowing what the reaction is and what other information was provided.

Even then, you need to show what you did so far. Please read the forum rules.