Answer: 4 moles
Explanation:

From the balanced chemical equation, it can be seen that 6 moles of lithium react with 1 mole of nitrogen to give 2 moles of lithium nitride.
Now as nitrogen is in excess, lithium is the limiting reagent as it limits the formation of products.
As 6 moles of lithium produce 2 moles of lithium nitride.
12 moles of lithium will produce=
of lithium nitride.