Weak Base Strong Acid Titrations Video Lessons

Concept:

Problem: Methylamine (CH3NH2) has a Kb = 4.4 x 10-4. If 100.0 mL of a 0.5000 M aqueous methylamine solution is mixed with 100.0 ml of 0.5000 M aqueous hydrochloric acid, the resulting solution will have a pHa. 5.88b. 6.12c. 6.81d. 7.24e. 7.72

FREE Expert Solution

We’re being asked to calculate the pH of a solution made by mixing 100.0 mL of 0.644 M CH3NHwith 100.0 mL of 0.100 M HCl.

We will calculate the pH of the solution using the following steps:

Step 1. Write the chemical equation for the reaction between CH3NH2 and HCl.
Step 2. Calculate the initial amounts of CH3NH2 and HCl in moles before the reaction happens.
Step 3. Construct an ICF Chart.
Step 4. Calculate the new concentration of the species left in the solution.
Step 5. Calculate pH.

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Problem Details

Methylamine (CH3NH2) has a Kb = 4.4 x 10-4. If 100.0 mL of a 0.5000 M aqueous methylamine solution is mixed with 100.0 ml of 0.5000 M aqueous hydrochloric acid, the resulting solution will have a pH

a. 5.88

b. 6.12

c. 6.81

d. 7.24

e. 7.72