Question
Which of the following statements is true concerning a solution formed by the addition of 0.1 mol of NH_3 and 0.1 mol of NaHSO_4 to 1.0 L of water? K_o for NH_3 is 1.8 times 10^-5 and ka for HSO_4^- is 1.1 times 10^-2. A) The solution is slightly acidic. B) The solution is very acidic. C)The solution is neutral. D) The solution is slightly basic. E) The solution is very basic. A solution contains 10. mmol of H_3 PO_4. and 5.0 mmol of NaH_2 PO_4. How many of the milliliters of 0.10 M NaoH must be added to reach the second equivalence point titration of the H_3 PO_4 with NaOH? A) 250 mL B) 150 mL C) 1.0 times 10^2 mL D) 50 mL. E) 2.0 times 10^2 mL
Explanation / Answer
Given
Solution will be slighlty acidic
equimolar NH3 and NaHSO4
Kb of NH3 is 1.8 * 10-5
Ka of HSO4 is 1.1 * 10-2
pH of solution = pKa1 + pKb1 = - log (1.1 * 10-2 ) - log (1.8 * 10-5 ) = 6.7
solution will be slightly acidic