All of the following statements concerning acid-base buffers are true EXCEPT (1.
ID: 1030059 • Letter: A
Question
All of the following statements concerning acid-base buffers are true EXCEPT (1.25 POINTS) s concerning buters are resistant to phí changes upon addition of small quantities of strong acids or bases buffers are used as colored indicators in acid-base titrations. the pH of a buffer is close to the pK, of the weak acid from which it is made. b. c. econtain appreciable quantities of a weak acid and its conjugate base. buffers are resistant to changes in pH when diluted with water. e. 5. Which is the best colored indicator to use in the titration of 0.1 M CHCO,H(aq) with NaOH(ag)? Whye R of Chico:H 1 .8 103, K, of CHC0% 55x 10"0) 125 POINTS pK. Bromcresol Green 6.8 9.2 Bromthymol Blue Phenolphthalein a. Bromcresol Green. The equivalence point for a weak acid titration occurs at low pH. b. Bromthymol Blue. The pH at the equivalence point is 7.0. c. Bromcresol Green. The pK, of CH CO H and the pK, of the indicator are similar. d. Phenolphthalein. The pK, of CH CO and the pks of the indicator are similar. e. Phenolphthalein. The pH at the equivalence point is near the pK, of the indicator. What is the molar solubility of Fe(OH)b(s) in a solution that is buffered at pH 2.50 at 25 C? The Kp of Fe(OH)s is 6.3x 10 at 25 °C. 1.25 POINTS a. 6.9 × 10-28 mol/L b. 2.0x 10- mol/L c. 1.3x 10- mol/L d. 2.0x 10 molL e. 5.0x 10 mol/L 6.Explanation / Answer
Answer 4. b)
No, Buffers are not used as indicators in acid base titrations, as it is a chemical solution that is resistant to changes in its pH as its pH is very stable.