Final answer:
When 45% of the H₂ leaks out, 55% of N₂ remains in the balloon and 45% leaks out through the pores.
Step-by-step explanation:
When 45% of the H₂ leaks out of a balloon filled with equal molar amounts of H₂ and N₂, we can use the concept of molar ratios to determine the % of N₂ remaining in the balloon. Since the molar ratio of H₂ to N₂ is 1:1, if 45% of the H₂ leaks out, then 45% of the N₂ will also leak out. Therefore, the % of N₂ remaining in the balloon is 100% - 45% = 55%.