11 8 AcidBase Titration The titration of an
11. 8 Acid–Base Titration The titration of an acid. A known volume of an acid is placed in a flask with an indicator and titrated with a measured volume of a base solution, such as Na. OH, to the neutralization endpoint. Learning Goal Calculate the molarity or volume of an acid or base from titration information. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Acid–Base Titration • is a laboratory procedure used to determine the molarity of an acid. • uses a base such as Na. OH to neutralize a measured volume of an acid. • requires a few drops of an indicator such as phenolphthalein to identify the endpoint. Core Chemistry Skill Calculating Molarity or Volume of an Acid or Base in a Titration General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Acid–Base Titration In the following titration, a specific volume of acidic solution is titrated to the endpoint with a known concentration of Na. OH. Base Na. OH Acid Solution General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Indicator The indicator phenolphthalein • is added to identify the endpoint. • turns pink when the solution is neutralized. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Endpoint of Titration At the endpoint of the titration, • the moles of base are equal to the moles of acid in the solution. • the concentration of the base is known. • the volume of the base used to reach the endpoint is measured. • the molarity of the acid is calculated using the neutralization equation for the reaction. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Guide to Calculating Boiling Point Elevation, Freezing Point Lowering General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Acid–Base Titration Calculations What is the molarity of an HCl solution if 18. 5 m. L of 0. 225 M Na. OH is required to neutralize 0. 0100 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 1 State given and needed quantities and concentrations. ANALYZE THE PROBLEM Given Need Equation 18. 5 m. L of molarity of HCl(aq) + Na. OH(aq) 0. 225 M Na. OH HCl solution Na. Cl(aq) + H 2 O(l) 0. 0100 L HCl General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Acid–Base Titration Calculations What is the molarity of an HCl solution if 18. 5 m. L of 0. 225 M Na. OH is required to neutralize 0. 0100 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 2 Write a plan to calculate molarity or volume. m. L Na. OH solution moles of Na. OH Metric factor Mole–Mole factor General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake L Na. OH solution moles of HCl Molarity Divide by liters moles of Na. OH molarity of HCl solution © 2016 Pearson Education, Inc.
Acid–Base Titration Calculations What is the molarity of an HCl solution if 18. 5 m. L of 0. 225 M Na. OH is required to neutralize 0. 0100 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 3 State equalities and conversion factors including concentration. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Acid–Base Titration Calculations What is the molarity of an HCl solution if 18. 5 m. L of 0. 225 M Na. OH is required to neutralize 0. 0100 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 4 Set up the problem to calculate the needed quantity. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Study Check What is the molarity of an HCl solution if 25. 5 m. L of 0. 438 M Na. OH is required to neutralize 0. 0250 L of HCl? HCl(aq) + Na. OH(aq) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake Na. Cl(aq) + H 2 O(l) © 2016 Pearson Education, Inc.
Solution What is the molarity of an HCl solution if 25. 5 m. L of 0. 438 M Na. OH is required to neutralize 0. 0250 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 1 State given and needed quantities and concentrations. ANALYZE THE PROBLEM Given Need Equation 25. 5 m. L of molarity of HCl(aq) + Na. OH(aq) 0. 438 M Na. OH HCl solution Na. Cl(aq) + H 2 O(l) 0. 0250 L HCl General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Solution What is the molarity of an HCl solution if 25. 5 m. L of 0. 438 M Na. OH is required to neutralize 0. 0250 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 2 Write a plan to calculate molarity or volume. m. L Na. OH solution Metric factor Mole–Mole factor General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake L Na. OH solution moles of HCl Molarity Divide by liters moles of Na. OH molarity of HCl solution © 2016 Pearson Education, Inc.
Solution What is the molarity of an HCl solution if 25. 5 m. L of 0. 438 M Na. OH is required to neutralize 0. 0250 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 3 State equalities and conversion factors including concentration. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
Solution What is the molarity of an HCl solution if 25. 5 m. L of 0. 438 M Na. OH is required to neutralize 0. 0250 L of HCl? HCl(aq) + Na. OH(aq) Na. Cl(aq) + H 2 O(l) STEP 4 Set up the problem to calculate the needed quantity. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
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