Answer:
4.73 mol (OPTION C)
Explanation:
In order to find the moles of Li produced by the reaction, we have to work from the known information (moles of barium), make a connection between the two species (mole ratio between barium and lithium), then we can calculate determine the moles of Lithium.
Balanced Equation:  2LiBr  +  Ba  →  BaBr₂  +  2Li
            moles = mass ÷ molar mass
Since the mass of barium is 325 g and its molar mass is 137 g/mol,
then the moles of barium = 325 g ÷ 137 g/mol
                     = 2.37 mol
Now to find the number of moles of Lithium, Â compare the mole ratio of Barium to Lithium based on the stoichiometric values of the balance equation:
   mole ratio of Ba : Li is 1 : 2
  ∴ for every moles of barium in the reaction, there are two moles of Lithium produced
⇒ if moles of Ba = 2.37 moles
then moles of Li = 2.37 moles × 2 moles
              =  4.74 moles (OPTION C)                 Â
