GATE MT 2019 Q38

Equilibrium concentration of dissolved nitrogen (in wt.%, rounded off to three decimal places) in pure liquid iron, exposed to atmospheric air at  1873 K, is                                                                                                           

Given: Sieverts’ law constant as a function of temperature (T; in Kelvin) is log₁₀ K _[N]  = [-518/T- 1.063], where 𝐾_[N]      has the dimension of 𝑎𝑡𝑚^-(1/2).

Assume [h_N] =[wt.% N] , where [h_N] is the activity of nitrogen with respect to 1 wt.% Henrian standard state.