Question

Aqueous hydrobromic acid HBr will react with solid sodium hydroxide NaOH to produce aqueous sodium bromide NaBr and liquid water H2O .

Suppose 60. g of hydrobromic acid is mixed with 48.8 g of sodium hydroxide. Calculate the minimum mass of hydrobromic acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.

Answer 1

HBr (aq) + NaOH   -----------------> NaBr (aq) + H2O (l)

   80.9 g          40 g                              102.9 g        18 g

60.0 g          48.8 g                             

here HBr is the limiting reagent.

80.9 g HBr ----------------> 40 g NaOH

       ??          -----------------> 48.8 g NaOH

mass of HBr = 48.8 x 80.9 / 40 = 98.7 g

we need 98.8 g HBr. but here we have only 60.0 g HBr. so this is limiting reagent.

no HBr will left over. all consumed