Question

Calculate the pH of an aqueous 0.0847 MP value on the homework or in the textbook. (6 pts) 3. us solution of 0.0847 M potassium nitrite, KNO2 (aq). Find the K 4. Which acid is stronger in the pair? And explain why from a structural standpoint (i.e. electronegativity, bond polarity, bond strength, number of atoms)? (2 pts each) HCIO or HCIO2 a. b. H2SO4 or H2SeO c. H3PO4 or HCIO

Answer 1

Ka of HNO2 4.5 x 104 Kb for NO2 is K 1x101 K. 4.5x101 = 2.22x10-11 NO2 in water is NO Initial 0.0847 0 0 Change Equilibrium 0.0847-x r.x_ = 2.22 × 10 0.0847-r x is small, so 0.0847-x 0.0847 r2-0.0847x2.22x101-1.88x1012 r1.37x106 [OH-] = x = 1.37 × 10-oM pOH-log[OH]-log (1.37x106 pH 14 pOH 14 -5.86-8.14 pH of 0.0847 M KNO, is 8.14 5.86

4. a) HCIO and HCIO2 as ihe number of oxynens bonded i.о ihe, ceniral aiorn increases, the oxidation numberof the central atom increases causing a weakening of the O-H bond strength and an increase in the acidity Hence HCIO, is stronger th an HCIo b) H2SO4 and H2Seo4 The acidity of the oxyacid depends on the electronegativity of the central atom. As the electronegativity increases, the-O-H bond wil be weaken and thus increases the acidity. Between S and Se, S is more electronegative atom and thus H2S04 is stronger than H2Seo (c) H3PO4 and HCIO The acidity of the oxyacid depends on the electronegativity of the central atom. As the electronegativity increases, the-O-H bond wl be weaken and thus increases the acidity. Between Cl and P, Cl is more electronegative atom and thus HCIO4 is stronger than H3PO4