A chemist needs to determine the concentration of a solution of nitric acid, HNO3 . She puts 725 mL of the acid in a flask along with a few drops of indicator. She then slowly adds 0.400 M Ba(OH)2 to the flask until the solution turns pink, indicating the equivalence point of the titration. She notes that 185 mL of Ba(OH)2 was needed to reach the equivalence point.
Solution map
In this titration, the concentration of base is known and can be used to calculate the unknown acid concentration:
concentration of base ? moles of base ? moles of acid ? concentration of acid
How many moles of Ba(OH)2 are present in 185 mL of 0.400 MBa(OH)2?