Find the limiting reaction for each initial amount of reactants in the following reaction:

2Na (s) + Br2 (g) -> 2NaBr (s)

Express your answer as a chemical formula.

1) 5 mol Na and 5 mol Br2

2) 2.9 mol Na and 2.5 mol Br2

3) 2.5 mol Na and 1 mol Br2

4) 12.4 mol Na and 6.9 mol Br2