Answer: Bromine is the limiting reactant
Explanation:
First of all let's generate a balanced equation for the reaction
2Li + Br2 —> 2LiBr
Molar Mass of Li = 7g/mol
Molar Mass of Br2 = 2x80 = 160g/mol
From the question given, were told that 25g of Li and 25g Br2 were present at the take-off of the reaction. Converting these Masses to mole, we have:
Number of mole of Li = 25/7 = 3.6moles
Number of mole of Br2 = 25/160 = 0.156mol.
To know which is the limiting reactant, we have to compare the ratio of the number of mole of experimental Li and Br2 to that of theoretical Li and Br2
For the experimental yield:
Li : Br2 = 3.6/ 0.156 = 23 : 1
For the theoretical yield:
Li : Br = 2 : 1
From the above, we see clear that Br2 is the limiting reactant because according to the equation( which gives the theoretical yield), for every 2moles of Li, 1mole of Br2 is used up. But this is not so from the experiment conducted as 23moles required 1mole of Br2.
