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Problem 80b
Using data from Appendix D, calculate 3OH-4 and pH for each of the following solutions: (b) 0.035 M Na2S
- A solution of sodium acetate (NaCH3COO) has a pH of 9.70. What is the molarity of the solution?
Problem 81
Problem 82a
Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqueous solution of pyridinium bromide has a pH of 2.95. (a) Write out the reaction that leads to this acidic pH.
Problem 82b
Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqueous solution of pyridinium bromide has a pH of 2.95. (b) Using Appendix D, calculate the Ka for pyridinium bromide.
Problem 82c
Pyridinium bromide 1C5H5NHBr2 is a strong electrolyte that dissociates completely into C5H5NH+ and Br-. An aqueous solution of pyridinium bromide has a pH of 2.95. (c) A solution of pyridinium bromide has a pH of 2.95. What is the concentration of the pyridinium cation at equilibrium, in units of molarity?
- Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral: (a) NH4Br (b) FeCl3 (c) KClO4 (d) NaHC2O4.
Problem 83
Problem 83c
Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral: (c) Na2CO3
Problem 84a
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (a) AlCl3
Problem 84b
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (b) NaBr
Problem 84c
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (c) NaClO
Problem 84d
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (d) 3CH3NH34NO3
Problem 84e
Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (e) Na2SO3.
Problem 85
An unknown salt is either NaF, NaCl, or NaOCl. When 0.050 mol of the salt is dissolved in water to form 0.500 L of solution, the pH of the solution is 8.08. What is the identity of the salt?
Problem 86
An unknown salt is either KBr, NH4Cl, KCN, or K2CO3. If a 0.100 M solution of the salt is neutral, what is the identity of the salt?
- Predict the stronger acid in each pair: (a) HNO3 or HNO2 (b) H2SO4 or H2SeO4 (c) CH3COOH or CCl3COOH.
Problem 87
- Predict the stronger acid in each pair: (b) H3PO4 or H3AsO4 (d) H2C2O4 or HC2O4⁻
Problem 88
Problem 88c
Predict the stronger acid in each pair: (c) HBrO3 or HBrO2
Problem 88e
Predict the stronger acid in each pair: (e) benzoic acid (C6H5COOH) or phenol (C6H5OH).
- Based on their compositions and structures and on conjugate acid–base relationships, select the stronger base in each of the following pairs: (a) BrO- or ClO- (c) HPO42- or H2PO4-
Problem 89
Problem 89b
Based on their compositions and structures and on conjugate acid–base relationships, select the stronger base in each of the following pairs: (b) BrO- or BrO2-
Problem 90b
Based on their compositions and structures and on conjugate acid–base relationships, select the stronger base in each of the following pairs: (b) PO43- or AsO43-
Problem 91c
Indicate whether each of the following statements is true or false. For each statement that is false, correct the statement to make it true. (a) In general, the acidity of binary acids increases from left to right in a given row of the periodic table. (b) In a series of acids that have the same central atom, acid strength increases with the number of hydrogen atoms bonded to the central atom. (c) Hydrotelluric acid 1H2Te2 is a stronger acid than H2S because Te is more electronegative than S.
Problem 92
Indicate whether each of the following statements is true or false. For each statement that is false, correct the statement to make it true. (a) Acid strength in a series of H¬A molecules increases with increasing size of A. (b) For acids of the same general structure but differing electronegativities of the central atoms, acid strength decreases with increasing electronegativity of the central atom. (c) The strongest acid known is HF because fluorine is the most electronegative element.
- Ammonia, NH3, acts as an Arrhenius base, a Brønsted-Lowry base, and a Lewis base, in aqueous solution. Write out the reaction NH3 undergoes with water and explain what properties of ammonia correspond to each of the three definitions of “base.”
Problem 93
- The fluoride ion reacts with water to produce HF. (c) Is fluoride acting as a Lewis acid or as a Lewis base when reacting with water?
Problem 94
Problem 95
Identify the Lewis acid and Lewis base among the reactants in each of the following reactions:
(a) Fe(ClO4)3(s) + 6 H2O(l) ⇌ [Fe(H2O)6]3+(aq) + 3 ClO4-(aq)
(b) CN-(aq) + H2O(l) ⇌ HCN(aq) + OH-(aq)
(c) (CH3)3N(g) + BF3(g) ⇌ (CH3)NBF3(s)
(d) HIO(lq) + NH2-(lq) ⇌ NH3(lq) + IO-(lq) (lq denotes liquid ammonia as solvent)
Problem 96
Identify the Lewis acid and Lewis base in each of the following reactions:
(a) HNO2(aq) + OH-(aq) ⇌ NO2-(aq) + H2O(l)
(b) FeBr3(s) + Br-(aq) ⇌ FeBr4-(aq)
(c) Zn2+(aq) + 4 NH3(aq) ⇌ Zn(NH3)42+(aq)
(d) SO2(g) + H2O(l) ⇌ H2SO3(aq)
- Predict which member of each pair produces the more acidic aqueous solution: (a) K+ or Cu2+ (b) Fe2+ or Fe3+ (c) Al3+ or Ga3+.
Problem 97
Problem 98
Which member of each pair produces the more acidic aqueous solution: (a) ZnBr2 or CdCl2 (b) CuCl or Cu(NO3)2 (c) Ca(NO3)2 or NiBr2
- Indicate whether each of the following statements is correct or incorrect. (e) The percent ionization of a weak acid in water increases as the concentration of the acid decreases.
Problem 99