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

Question

Suppose 46.1 g of hydrobromic acid is mixed with 10. g of sodium hydroxide. Calculate the maximum mass of sodium bromide that could be produced by the chemical reaction. Round your answer to 2

 significant digits.

= ______ g

Answer 1

First, write the correctly balanced equation for the reaction taking place:

HBr(aq) + NaOH(s) ==> NaBr(aq) + H2O(l) ... balanced equation

Next, find out which reactant is limiting. An easy way is to just divide the moles of each reactant by the corresponding coefficient in the balanced equation (1 for both in this case):

HBr: 46.1 g HBr x 1 mol HBr / 80.9 g = 0.570 moles

NaOH: 10. g NaOH x 1 mol NaOH / 40. g = 0.25 mols NaOH

NaOH is limiting and will determine the maximum amount of product that can form.

Maximum amount of NaBr that can form:

0.25 mols NaOH x 1 mol NaBr / 1 mol NaOH x 103 g NaBr / mol = 25.75 g NaBr = 26 g NaBr (2 s.f.)