Question

A 25.00- mL sample of an HNO3 solution is titrated with 0.143 M NaOH . The titration requires 28.83 mL to reach the equivalence point. What is the concentration of the HNO3 solution? 0.165 M 12.4 M 0.1240 M 0.143 M

Answer 1

The concentration of the HNO3 solution is found by calculating the moles of NaOH used at the equivalence point and assuming a 1:1 molar reaction ratio with HNO3. We then divide the moles of HNO3 by the volume of the HNO3 solution to get the concentration, which is approximately 0.165 M.

Step-by-step explanation:

To determine the concentration of the HNO3 solution that was titrated with 0.143 M NaOH, we utilize the concept of stoichiometry and the reaction equation between NaOH and HNO3, which is:

HNO3 + NaOH → NaNO3 + H2O

Since both reactants react in a 1:1 molar ratio and the volume and molarity of NaOH used are known, we can calculate the moles of NaOH used at the equivalence point:

Moles of NaOH = Molarity of NaOH × Volume of NaOH in liters = 0.143 mol/L × 0.02883 L = 0.00412309 mol

Given the 1:1 molar ratio, the moles of HNO3 will be the same as the moles of NaOH at the equivalence point, 0.00412309 mol. To find the concentration of HNO3, we now divide the moles of HNO3 by the volume of HNO3 solution in liters:

Concentration of HNO3 = Moles of HNO3 / Volume of HNO3 in liters = 0.00412309 mol / 0.02500 L = 0.164924 M

Therefore, the concentration of HNO3 solution is approximately 0.165 M.