Question

Consider the titration of 1.0 L of 1.0 M NH3 with 1.0 M HCl. Which of the following correctly describe(s) how the pH would be calculated at each of the following additions of HCl? I: At 0 L HCl, pH would be calculated based on the concentration and Kb of the weak base II: At 1 L HCl, pH would be calculated based on the concentration and Ka of the conjugate acid III: At 2 L HCl, pH would be calculated based on the concentration of excess acid in solution Group of answer choices I and III Only II Only I I, II, and III II and III

Answer 1

I, II, and III

Step-by-step explanation:

In the titration of NH₃ with HCl:

NH₃ + HCl → NH₄⁺ + Cl⁻

Where NH₃ is the weak base and NH₄⁺ is the conjugate acid.

I: At 0 L HCl, pH would be calculated based on the concentration and Kb of the weak base: At 0L of HCl, you will have just NH₃ in solution. That means you would calculate the pH just from the concentration of the weak base using Kb. That means I is true.

II: At 1 L HCl, pH would be calculated based on the concentration and Ka of the conjugate acid: When you add 1L of HCl, you will have in solution just NH₄⁺, the conjugate acid. That means you would calculate the pH of the solution just with the Ka of the conjugate acid and its concentration. II is true.

III: At 2 L HCl, pH would be calculated based on the concentration of excess acid in solution: At 2L of HCl solution, you have HCl in excess in the solution. As HCl is a strong acid, the pH would be affected in the big way by this concentration in excess. III is true.