Question

On a lab exam, you have to find the concentrations of the monoprotic (one proton per molecule) acids HA and HB. You are given 43.5 mL of HA solution in one flask.You titrate this flask of HA solution with 87.3 mL of 0.0906 M NaOH. Calculate the molarity of the HA solution

Answer 1

To find the molarity of the HA solution, calculate the number of moles of NaOH used in the titration and use the ratio of moles of HA to moles of NaOH to determine the number of moles of HA in the solution. Then, calculate the molarity of the HA solution using the moles of HA and the volume of the solution.

Step-by-step explanation:

To find the molarity of the HA solution, we can first calculate the number of moles of NaOH used in the titration. The balanced chemical equation for the reaction between HA and NaOH is:

HA + NaOH → NaA + H2O

From the equation, we can see that the ratio of moles of HA to moles of NaOH is 1:1. We can use the molarity and volume of NaOH used in the titration to calculate the number of moles of NaOH, and since the ratio is 1:1, this will also be the number of moles of HA in the solution.

First, we calculate the number of moles of NaOH:

Moles of NaOH = Molarity of NaOH * Volume of NaOH

= 0.0906 M * 0.0873 L

= 0.0078958 mol NaOH

Since the ratio of moles of HA to moles of NaOH is 1:1, the number of moles of HA in the solution is also 0.0078958 mol.

Now, we can calculate the molarity of the HA solution:

Molarity of HA = Moles of HA / Volume of HA solution

= 0.0078958 mol / 0.0435 L

= 0.181 M