Stoichiometric volume ratio for ammonia formation

Steps:

• Recall the balanced equation: N₂ + 3H₂ → 2NH₃.
• Note that for gases at same T/P, volumes proportional to moles (Avogadro's law).
• Given mixture ratio N₂:H₂ = 1:3 by volume matches reaction's 1:3 mole/volume ratio.
• Thus, complete reaction occurs with no excess reactants.

Why B is correct:

• B states the mixture is stoichiometric, aligning with the 1:3 volume ratio required by the reaction formula.

Why the others are wrong:

• A ignores Avogadro's law, assuming volume ratios differ from mole ratios.
• C claims excess hydrogen, but 1:3 exactly matches stoichiometry.
• D suggests incomplete reaction, overlooking the precise ratio for full conversion.

Not enough information on exact choices, but B fits standard stoichiometric confirmation.

Final answer: B