What is the mass of NaClO 2 required to create abuffer solution of pH = 2.5 from

Question

What is the mass of NaClO2 required to create abuffer solution of pH = 2.5 from a 500 ml of HClO2(aq)(0.01 M)? Assume negligible change in the original concentration ofHClO2 due to the presence of addedClO2 anions. These are the answers to choose from. A. 2.95 B. 1.85 C. 1.45 D. 2.00 What is the mass of NaClO2 required to create abuffer solution of pH = 2.5 from a 500 ml of HClO2(aq)(0.01 M)? Assume negligible change in the original concentration ofHClO2 due to the presence of addedClO2 anions. These are the answers to choose from. A. 2.95 B. 1.85 C. 1.45 D. 2.00 A. 2.95 B. 1.85 C. 1.45 D. 2.00

Explanation / Answer

               pH of the buffer solution formed by the HClO2 and NaClO2 is                      pH   = pKa   + log[NaClO2] / [HClO2]                         Number of moles of HClO2   = 0.01M * 0.5 L                                                                     = 0.005 mol                                                 let the number of moles of NaClO2 = x                        2.5 = -log Ka   + log x / 0.005 mol                                =   - log ( 1.1 * 10-2 ) + log x/ 0.005 mol                         Number of moles of NaClO2 =   0.0173 mol                  mass of NaClO2 added = 0.0173mol * 90.44 g/mol                                                              = 1.572 g

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

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