A solution containing 10. mmol of CO₃²^- and 5.0 mmol of HCO₃^- is titrated with 1.0 M HCl.
What volume of HCl must be added to reach the first equivalence point?

Question

A solution containing 10. mmol of CO₃²^- and 5.0 mmol of HCO₃^- is titrated with 1.0 M HCl. What volume of HCl must be added to reach the first equivalence point?

Quizplus · Accepted Answer

The first step is to write out the balanced chemical equation for the reaction between CO₃²^- and HCl: CO₃²^- + 2HCl -> ₃^- + H2O + CO2 From the equation, we can see that the stoichiometric ratio of CO₃²^- to HCl is 1:2. This means that to reach the first equivalence point, we will need to add enough HCl to react with all 10 mmol of CO₃²^-. The amount of HCl required can be calculated using the following formula: moles of HCl = (moles of CO₃²^-) x 2 moles of HCl = 10 mmol x 2 = 20 mmol Now we can use the definition of molarity (M) to calculate the volume of 1.0 M HCl required to provide 20 mmol of HCl: M = moles of solute / volume of solution rearranging, we get: volume of solution = moles of solute / M volume of solution = 20 mmol / 1.0 mol/L = 20 mL Therefore, the correct answer is C) 10 mL, as this is the volume of HCl required to reach the first equivalence point.

A Solution Containing 10