A buffered solution is made by adding 47.4 g C2H5NH3Cl to 1.00 L of a 0.68 M solution of C2H5NH2. Calculate the pH of the final solution. (Assume no volume change. Assume that all solutions are at 25°C.)

Answer 1

Convert 47.4 g C2H4NH3Cl to mols. mols = grams/molar mass = ?. Since that is in 1 L solution, that will be the molarity. This is the acid.
You have 0.68 M solution of C2H4NH2 which is the base.
Substitute into the Henderson-Hasselbalch equation, and solve for pH.