Question

1. if 15.27 mL of 0.250 M solution of barium hydroxide is required to reach the equivalence point in a titration of 20.00 mL of nitric acid, what is the concentration of the acid? The equation for the reaction is

2 HNO3 + Ba(OH)2 --> 2 H2O + 2 NO3- + Ba2+

2. For the reaction:

HCOOH + OH- --> HCOO- + H2O

If 24.60 mL of base is required to reach the equivalence point of this titration, what volume of base is required to reach the point where pH = pKa?

Answer 1

1. According to reaction

Ba(OH)₂+ 2HNO₃ 2H₂O + 2NO₃^- + Ba⁺²

so that the mole ratio

Ba(OH)₂ : 2HNO₃

1 : 2

Amount of  Ba(OH)₂ consumed

0.250 x 15.27/1000 = .00381 mol

so that amount of  HNO₃

2 x .00381= .00763 mol

If the molarity of HNO₃ is a then

a x 20.00 /1000 = .00763

a= 0.381 M ( concentration of HNO3)

2. if molarity of both solution will be same then

volume of solution will be also same

according

M₁V₁=M₂V₂