ANS:A - 1

The value of 𝑁𝐴𝑁𝐴+𝑁𝐵NA​+NB​NA​​ for steady-state molecular diffusion of gas 'A' through non-diffusing gas 'B' can be determined from Graham's Law of Effusion, which states that the rate of effusion or diffusion of a gas is inversely proportional to the square root of its molar mass. Mathematically, the ratio 𝑁𝐴𝑁𝐴+𝑁𝐵NA​+NB​NA​​ can be expressed as: 𝑁𝐴𝑁𝐴+𝑁𝐵=𝑀𝐵𝑀𝐴+𝑀𝐵NA​+NB​NA​​=MA​​+MB​​MB​​​ Where:

• 𝑁𝐴NA​ is the molar flux of gas 'A',
• 𝑁𝐵NB​ is the molar flux of gas 'B',
• 𝑀𝐴MA​ is the molar mass of gas 'A',
• 𝑀𝐵MB​ is the molar mass of gas 'B'.

In this scenario, gas 'B' is considered as the non-diffusing gas, implying that its molar flux (𝑁𝐵NB​) is negligible compared to gas 'A'. Therefore, the value of 𝑁𝐴𝑁𝐴+𝑁𝐵NA​+NB​NA​​ approaches 1, which is the limit as 𝑀𝐵MB​ approaches infinity. So, the correct answer is 1.