Question

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants.
2Na(s)+Br2(g)→2NaBr(s)

1- 5 mol Na, 5 mol Br2

Express your answer as a chemical formula.

2- 2.1 mol Na, 1.7 mol Br2

Express your answer as a chemical formula

3- 2.5 mol Na, 1 mol Br2

Express your answer as a chemical formula.

4-   12.5 mol Na, 6.9 mol Br2

Express your answer as a chemical formula.

Answer 1

1)

5 mol Na, 5 mol Br2 :

Let us consider the given reaction,

2Na(s)+Br2(g)→2NaBr(s)

From the reaction ,
1 mole Br2 ---> 2 mole of Na
5 mole Br2 = (2*5) mole of Na
= 10 mole of Na
but we have 5 mole of Na
so, Na is limiting agent

2)

2.1 mol Na, 1.7 mol Br2

Let us consider the given reaction,

2Na(s)+Br2(g)→2NaBr(s)

From the reaction ,

1 mole Br2 --- > 2 mole of Na
1.7 mole Br2 = (2*1.7) mole of Na
= 3.4 mole of Na
but we have only 2.1 mole of Na
so, Na is limiting agent

3)

2.5 mol Na, 1 mol Br2:

Let us consider the given reaction,

2Na(s)+Br2(g)→2NaBr(s)

From the reaction ,

1 mole Br2 required 2 mole of Na

we have 2.5 mole of Na

so, Na is in excess and Br2 is limiting reagent

4)

12.5 mol Na, 6.9 mol Br2

Let us consider the given reaction,

2Na(s)+Br2(g)→2NaBr(s)

From the reaction ,

1 mole Br2 --->2 mole of Na
6.9 mole Br2 = (2*6.9) mole of Na
= 13.8 mole of Na
but we have only 12.5 mole of Na
so, Na is limiting agent