Question

Tutored Practice Problem 17.2.7 COURS TOWARDS CITIDE Prepare a buffer by acid-base reactions. Close Problem Consider how to prepare a buffer solution with pH = 9.07 (using one of the weak acid/conjugate base systems shown here) by combining 1.00 L of a 0.436-M solution of weak acid with 0.317 M potassium hydroxide. к. Weak Acid HNO2 HCIO HCN Conjugate Base NO2 CIO CN 4.5 x 104 3.5 x 108 4.0 x 10-10 pK, 3.35 7.46 9.40 How many L of the potassium hydroxide solution would have to be added to the acid solution of your choice? Check & Submit Answer Show Approach Alpha Plots As shown in the preceding example problems, the pH of a buffer solution is controlled by the relative amounts of weak acid and conjugate base present and by the weak acid pK,. That is, buffer pH is independent of solution volume. If a buffer solution is diluted, the pH does not change. Regardless of the amounts of weak acid and conjugate base that are present in the solution, however the

Answer 1

(C.B ) [Acid] PH=pkat closest raulue of PH & p ka is in HCN. Na CN & HOH o o before RXN HCN + NaOH 0.436 0.317& V 0•317V 0.436-0-317V pH = 9.4+ log (0.317 V 0-436-0-317V) 0.31AV 9:07 = 9.4 +10g ( 01436-09317V) 0.317 V = 0.43 0.436-0-3178 =) (0.319 +0.135 ) V= 0.186 = v= 0.4113 lt. 411.3 ml