Problem 110
Predict whether a solution containing the salt \(\mathrm{K}_{2} \mathrm{HPO}_{4}\) will be acidic, neutral, or basic.
Problem 111
Predict the \(\mathrm{pH}(>7,<7,\) or \(\approx 7)\) of a \(\mathrm{NaHCO}_{3}\) solution.
Problem 112
Classify the following oxides as acidic, basic, amphoteric, (c) CaO, (e) CO, or neutral: (a) \(\mathrm{CO}_{2}\), (b) \(\mathrm{K}_{2} \mathrm{O}\) (d) \(\mathrm{N}_{2} \mathrm{O}_{5}\) (f) \(\mathrm{NO},(\mathrm{g}) \mathrm{SnO}_{2},\) (i) \(\mathrm{Al}_{2} \mathrm{O}_{3},(\mathrm{j}) \mathrm{BaO}\) (h) \(\mathrm{SO}_{3}\)
Problem 113
Write equations for the reactions between (a) \(\mathrm{CO}_{2}\) and \(\mathrm{NaOH}(a q),(\mathrm{b}) \mathrm{Na}_{2} \mathrm{O}\) and \(\mathrm{HNO}_{3}(a q)\)
Problem 114
Explain why metal oxides tend to be basic if the oxidation number of the metal is low and tend to be acidic if the oxidation number of the metal is high. (Hint: Metallic compounds in which the oxidation numbers of the metals are low are more ionic than those in which the oxidation numbers of the metals are high.)
Problem 115
Arrange the oxides in each of the following groups in order of increasing basicity: (a) \(\mathrm{K}_{2} \mathrm{O}, \mathrm{Al}_{2} \mathrm{O}_{3}, \mathrm{BaO},\) (b) \(\mathrm{CrO}_{3}, \mathrm{CrO}, \mathrm{Cr}_{2} \mathrm{O}_{3}\)
Problem 116
\(\mathrm{Zn}(\mathrm{OH})_{2}\) is an amphoteric hydroxide. Write balanced ionic equations to show its reaction with (a) \(\mathrm{HCl}\), (b) \(\mathrm{NaOH}\) [the product is \(\left.\mathrm{Zn}(\mathrm{OH})_{4}^{2-}\right]\).
Problem 117
\(\mathrm{Al}(\mathrm{OH})_{3}\) is insoluble in water. It dissolves in concentrated NaOH solution. Write a balanced ionic equation for this reaction. What type of reaction is this?
Problem 118
What are the Lewis definitions of an acid and a base? In what way are they more general than the Brønsted definitions?
Problem 119
In terms of orbitals and electron arrangements, what must be present for a molecule or an ion to act as a Lewis acid (use \(\mathrm{H}^{+}\) and \(\mathrm{BF}_{3}\) as examples)? What must be present for a molecule or ion to act as a Lewis base (use \(\mathrm{OH}^{-}\) and \(\mathrm{NH}_{3}\) as examples)?
