4. Water with a pH of 9.5 is known to have a buffer of 120mg/L as CaCO3eq. a. Find the molar concentrations of the carbonate and bicarbonate ions {2.7 x 10-4, 1.8 x 10-³} b. If 25mL of 2% HCI is added to 0.12m³ of water, what is the new pH? {9.23} c. What is the maximum volume of 2% HCI that can be added to 0.12m³ of water before the pH drops below 9? (38mL)

the ksp of calcium hydroxide is 4.86x10^-6

7. A solution was made by mixing 50.0 mL of 0.750 M HCN with 25.0 mL of water. What is the pH of this solution? The pka of HCN = 9.31. 8. One of the compounds featured on the TV series "Breaking Bad" was hydrofluoric acid (HF), pKa = 3.14. a) A solution of HF has a pH = 1.77. What was the initial [HF] for this solution in mol L-1? b) What is the equilibrium concentration of F in this solution in mol L-1? c) What is the percent ionization of HF in this solution?

24. How many moles of NH,Br must be added to 2 L of 0.1 M NH,OH to form a buffer whose pH is 9.00? (K, of NH,OH = 1.76 x 0*)

5. a. Suppose a solution contains 0.50 M NaH2PO4 and 0.80 M Na2HPO4. What pH should be expected for this buffer solution? Uw we made aw bufter b. Calculate the final pH if 5.0 mL of 0.10 M NAOH is added to 20.0 mL of this buffer solution. it +corected

#9 plz