Define buffer by a. composition b. properties. What are the expected pHs of the

Question

Define buffer by a. composition b. properties. What are the expected pHs of the following solution of carbonate buffer? c. 0.45 M carbonic acid (H_2CO_3) with 0. 45 M sodium carbonate (NaHCO_3) d. 0. 45 M carbonic acid (H_2CO_3) with 0.045 M sodium carbonate (NaHCO_3) e. 0.045 M carbonic acid (H_2CO_3) with 0. 45 M sodium carbonate (NaHCO_3) f. 0.86 M carbonic acid (H_2CO_3) with 0.86 M sodium carbonate (NaHCO_3) g. What are the two characteristics of the best buffers? (different than parts a & b) h. Analyze the four solutions above. Which is best overall buffer, and why?

Explanation / Answer

Buffer

a. Composition : A buffer is a combination of weak acid/conjugate base or weak base/conjugate acid.

b. Properties : A buffer is a combination of weak acid/conjugate base or weak base/conjugate acid which resists any change in pH by the addition of base or acid to it.

pH of buffer by Hendersen-Hasselbalck equation,

pH = pKa + log(base/acid)

c. pH = 6.35 + log(0.45/0.45) = 6.35

d. pH = 6.35 + log(0.045/0.45) = 5.35

e. pH = 6.35 + log(0.45/0.045) = 7.35

f. pH = 6.35 + log(0.86/0.86) = 6.35

g. Best buffer : Is one which resist the pH change to the maximum. A high concentration buffer solution is generally the best buffer system.

h. Best overall buffer among the given combinations is, f. whch has 0.86 M of weah acid H2CO3 and its conjugate base NaHCO3

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.