Question

An aqueous solution of hydrobromic acid is standardized by titration with a 0.149 M solution of calcium hydroxide.

If 15.9 mL of base are required to neutralize 17.4 mL of the acid, what is the molarity of the hydrobromic acid solution?

M hydrobromic acid

Answer 1

balanced eqaution is

Ca(OH)2 + 2 HBr -----> 2 H2O + CaBr2

number of moles of base = molarity * volume of solution in L

number of moles of base = 0.149*0.0159 = 0.00237 mole

from the balanced equation we can say that

1 mole of base requires 2 mole of hydrobromic acid so

0.00237 mole of base will require 0.00474 mole of hydrobromic acid

Molarity = number of moles of HBr / volume of solution in L

molarity = 0.00474 / 0.0174 = 0.272 M

Therefore, the molarity of hydrobromic acid is 0.272 M