Question

50.0 mL of an HNO3 solution were titrated with 36.90 mL of a 0.100 M LiOH solution to reach the equivalence point. What is the molarity of the HNO3 solution

Answer 1

Following reaction takes place between LiOH and HNO3

LiOH    +  HNO3        →        LiNO3      +       H2O

Thus, 1 mole of LiOH reacts with 1 mole of HNO3 to form 1 mole of LiNO3.

Now, 
Number of millimoles of LiOH consumed = 36.90 X 0.100 = 3.690

∴Number of millimoles of HNO3 present = 3.690

Now, Molarity of HNO3 = $\frac{\text{number of millimoles of HNO3}}{\text{volume of solution (ml)}}$
                                      =   $\frac{3.690}{50}$ = 0.0738 M

Thus, molarity of the HNO3 solution is 0.0738 M