Question

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)

Answer 1

Answer:

See explanation

Explanation:

The equation of the reaction is;

2HNO3(aq) + Ba(OH)2(aq) -------->Ba(NO3)2(aq) + 2H2O(l)

a) The number of moles of  Ba(OH)2  = 225/1000 *  0.200

= 0.045 moles

From the reaction equation;

2 moles of HNO3 require 1 mole of  Ba(OH)2

x moles of HNO3 require 4.50 x 10^2 mol of Ba(OH)2

x = 4.50 x 10^2 * 2/1

x = 9  x 10^2 moles of HNO3