A chemist needs to determine the concentration of a solution of nitric acid, HNO3. She puts 905 mL of the acid in a flask along with a few drops of indicator. She then slowly adds 0.200 M Ba(OH)2 to the flask until the solution turns pink, indicating the equivalence point of the titration. She notes that 235 mL of Ba(OH)2 was needed to reach the equivalence point. Required:
a. How many moles of Ba(OH)2 are present in 225 mL of 0.200 M Ba(OH)2?
b. How many moles of HNO3 are present if 4.50 x 10^2 mol of Ba(OH)2 was needed to neutralize the acid solution? (Express your answer numerically in moles)