Question

One handbook lists a value pKb= 9.5 for of quinoline,C9H7N , a weak base used as a preservative for anatomical specimens and to make dyes. Another handbook lists the solubility of quinoline in water at 25degree celsius as 0.6g/100mL.

calculate the pH of a saturated solution of quinoline in water.

Answer 1

C9H7N + H2O ==> C9H7NH^+ + OH^-
Set up an ICE chart and solve for OH^- after converting pKb to Kb. You will need the concn C9H7N which can be obtained from the solubility. If solubility is 0.6g/100 mL, that means 6g/L so convert 6g to moles (moles = grams/molar mass).
Finally, convert OH^- to pOH, then to pH. Post your work if you get stuck.