Polyprotic acid and Buffer Equilibrium Questions 1. Explain what happens to a) T
ID: 1044371 • Letter: P
Question
Polyprotic acid and Buffer Equilibrium Questions 1. Explain what happens to a) The b) The percentage deprotonation of benzoic acid in a benzoic acid solution when hydrochloric acid e concentration of IO ions in an acetic acid solution when solid sodium acetate is added. is added c) The pH of the solutio n of an aqucous ammonia solution when solid ammonium chloride is added 2. A solution of equal concentrations of glyceric acid and sodium glycerate was found to have a pH of 3.52 a) What are pK, and K, for glyceric acid? b) What would the pH be if the concentration of acid was twice that of the salt? 3. Sodium hypochlorite, NaOC, is the active ingredient in many bleaches. Calculate the ratio of the concentrations ofCO and HCO n a bleach solution having a pH adjusted to 6.50 by the use of strong acid or strong base. (K 3.0 x 10* for HCIO) 4. Calculate the pH and pOH of a solution that contains 0.200 M of sulfurous acid, H,SO,. (K, for sulfurous acid is 1.39 × 10'. Aw is 673 × 10") 5. Calculate the pH and pOH of a buffer solution that contains 0.250 MM of acetic acid and 0.100 M sodium acetate. (K, for acetic acid, CH,COOH is 1.8 10") 6. Calculate the pH of the solution that results from mixing 30.0 mL of 0.050 M HCN(ag) with 70.0 mL of 0.030 M NaCN(ag). (K fr HCN is 62 × 10") 7. A buffer solution of volume 100.0 ml. consists 0.100 MCH COOH(a) and 0.100 M NaCH,COO(ag). What are the phi of the solution and the pH change that result from the addition of 10.0 mL of 0.950 M NaOH (ag) to the buffer solution? (K, CH COOH is 1.8 × 107 8. A buffer 250-ml. solution originally contains 0.0150 M sodium hydrogen carbonate, NaHCO, and 0.0110 M sodium carbonate. Na CO,. Calculate the pH of the buffer system. To the buffer solution are added 2.25 × 10' moles of HCL Calculate the pH of the buffer system now assuming no change in volume. (???. A. 50 x 10") 9. Citric acid, HOOCC(OH)(CHCOOH), is a polyatomic acid that is found in citrus fruits. After preparing a 0.100 M solution of the acid, calculate the pH and pOH of the solution. (K, for citric acid is 7.4 x 10 Ko is 1.7 x 10, and K, is 4.1 x 10)Explanation / Answer
Answer:
5) From the Henderson–Hasselbalch equation,
pH=pKa+log[salt]/[acid]
Given Ka of acetic acid=1.8x10^-5,then pKa=- log Ka
pKa=- log(1.8x10^-5)=4.7447
Acid is acetic acid, [Acid]=0.25 M
andsalt is sodium acetate, [Salt]=0.1 M
Then pH=4.7447+ log(0.1)/(0.25)
pH=4.7447-0.39794
pH=4.35.
We know that pH+POH=14, the pOH=14-pH
pOH=14-4.35=9.65.
Therefore pH=4.35 and pOH=9.65.
Thanks and I hope you like it. Please let me know if you have any doubt.