What is the pH of a buffer system that contains 0.24 M NH4+ and 0.12 M NH3? The pKa of NH4+ is 9.25.

Express your answer using two decimal places.

2. Titration of a 23.0 mL solution of KOH requires 13.0 mL of 0.0250 M H2SO4 solution.

What is the molarity of the KOH solution?

3. A solution is prepared by bubbling 20 L of HCl(g) at 36 ∘C and 1 atm into 300 mL of water.

Assuming all the HCl dissolves in the water, how many moles of HCl are in solution?

Express your answer using two significant figures and include the appropriate units.

4.What is the pH of the solution in 3?

Express your answer using two decimal places.

5.The active ingredient in aspirin is acetylsalicylic acid (MW=180.2g/mol). An aspirin tablet was dissolved in water and titrated with 0.100 MNaOH.

If the titration required 10.45 mL of NaOH to reach the phenolphthalein endpoint, how many milligrams of acetylsalicylic acid were in the tablet?