How do you do titration problems to find molarity?

Question

Naomi Aronson · Accepted Answer

See below.

Titration is used to determine the unknown molarity (#M#) of a solution (called analyte) using a titrant, which is a solution of known concentration.

Considering the analyte is an acidic solution (unknown molarity) and that it will be titrated using a basic solution with a known molarity (assuming monoprotic acid and base).

At the equivalence point, the number of mole of #H^+# ions will be equal to the number of mole of #OH^-# ions:

#n_(H^+)=n_(OH^-)#

Note that the relationship between molarity and number of mole is:

#M=n/V# where #V# is the volume of the solution.

Thus, #n=MxxV#.

Therefore, #M_(a)xxV_(a)=M_(b)xxV_(b)#

#=>M_(a)=(M_(b)xxV_(b))/(V_(a))#

Here is a video that fully explains this topic:
Lab Demonstration | Acid - Base Titration.

Noah Aldrich · Answer

undefined To do titration problems to find molarity, you need to follow these steps:

1. Measure a volume of the solution with known concentration (the titrant) using a burette.
2. Add the titrant to a known volume of the solution with unknown concentration (the analyte) in a flask.
3. The titrant reacts with the analyte until the reaction reaches the equivalence point.
4. Determine the volume of titrant used to reach the equivalence point.
5. Use the balanced chemical equation of the reaction to find the mole ratio between the titrant and analyte.
6. Use the volume and mole ratio to calculate the number of moles of the analyte.
7. Finally, use the number of moles of the analyte and its volume to calculate the molarity of the analyte solution.

Wyatt Atkins · Answer

undefined To find the molarity in a titration problem, follow these steps:

1. **Setup**: Write the balanced chemical equation for the reaction occurring in the titration. Note the mole ratio between the reactants.

2. **Determine Volume and Molarity of Solution**: Measure the volume of the solution in the burette (titrant) and its molarity.

3. **Titration Calculation**: During titration, record the volume of titrant needed to reach the endpoint, where the reaction is complete.

4. **Calculate Moles of Titrant**: Use the volume and molarity of the titrant to calculate the moles of the titrant used in the reaction.

5. **Apply Stoichiometry**: Use the balanced chemical equation to determine the mole ratio between the titrant and the substance being titrated (analyte).

6. **Calculate Moles of Analyte**: Use the mole ratio from step 5 to find the moles of analyte that reacted with the titrant.

7. **Determine Volume of Analyte**: If necessary, convert the moles of analyte to volume using its concentration.

8. **Calculate Molarity of Analyte**: Finally, calculate the molarity of the analyte using the moles and volume of the analyte.

The key is to use stoichiometry and the known quantities (volume and molarity) of the titrant and analyte to determine the unknown, which is typically the molarity of the analyte.