..ooo AT&T; 11:13 AM 5. Preparing a buffer: Which acid would you choose to combi
ID: 945509 • Letter: #
Question
..ooo AT&T; 11:13 AM 5. Preparing a buffer: Which acid would you choose to combine with its sodium salt to make a solution buffered at pH 7.35 For the best choice, calculate the ratio of the conjugate base to the acid recquired to attain the desired pH. Chlorous Acid (HCIO2) Nitrous Acid (HNO2) Formic Acid (HCHO2) Hypochlorous Acid (HCIO) pKa-1.95 pKa = 3.34 pKa = 3.74 pKa-7.54 6. Strong acid- strong base titration pH curve: Calculate the pH in the titration in example 6 after the addition of 60.0 mL of 0.200 M HNO3 7. Weak acid-strong base titration curve: Determine the pH of at the equivalence point for the titration of HNO2 and KOH in example 7
Explanation / Answer
To choose an acid with its sodium salt to make a solution buffered of pH=7.35 is best it that which have nearest pKa .Thus in this case we will use HClO.
pH = pKa + log [ClO-]/ [HClO]
7.35 = 7.54 + log [ClO-]/ [HClO]
- 0.19 = log [ClO-]/ [HClO]
10^-0.19 = [ClO-]/ [HClO]
[ClO-]/ [HClO] = 0.65
Thus to prepare buffer of 7.35 pH we use HClO and its sodium salt in ratio of 0.65.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.