ANS:B - ∞

In steady-state equimolal counter-diffusion, the molar fluxes of the two gases, 𝑁𝐴NA​ and 𝑁𝐵NB​, are equal and opposite in direction, resulting in no net flow of either gas across the system. The value of 𝑁𝐴𝑁𝐴+𝑁𝐵NA​+NB​NA​​ can be calculated as: 𝑁𝐴𝑁𝐴+𝑁𝐵=𝑁𝐴𝑁𝐴−𝑁𝐴=10NA​+NB​NA​​=NA​−NA​NA​​=01​ However, division by zero is undefined. In the case of steady-state equimolal counter-diffusion, the molar flux of one gas is equal in magnitude but opposite in direction to the molar flux of the other gas. Therefore, the correct answer would be: 𝑁𝐴𝑁𝐴+𝑁𝐵=11+1=12=0.5NA​+NB​NA​​=1+11​=21​=0.5 So, the correct option is 0.5.