Principles of Descriptive Inorganic Chemistry

Gary Wulfsberg

Chapter 2 Metal Cations and Oxo Anions in Aqueous Solution - all with Video Answers

Educators

Chapter Questions

Problem 1

Give two examples of metal (or nonmetal) cations for each of the following categories: a. Gives a neutral solution in water; b. gives a faintly acidic solution in water, but the acidity is masked by that due to dissolved carbon dioxide; c. gives a weakly acidic solution (comparable in acidity to vinegar); d. hydrolyzes reversibly to give a strongly acidic solution; e. hydrolyzes irreversibly in water.

Amy Jiang

Numerade Educator

01:54

Problem 2

Consider the following cations: $\mathbf{a} . \mathrm{U}^{3+}$;
e. $\mathrm{As}^{3+}$;
f. $\mathrm{Tl}^{+}$;
g. $\mathrm{Th}^{4+}$.
b. $\mathrm{Ag}^{+}$;
c. $\mathrm{Pa}^{5+}$;
d. $\mathrm{C}^{4+}$;
2.1 Classify the acidity of each of these cations and describe the reactions of their chlorides with water.
2.2 Which of these would give cloudiness or precipitation upon dissolving in water? What could you do to rectify this if it occurred?
2.3 If the solutions of these were adjusted to final $\mathrm{pH}$ 's of 5.5 to 7 , in what chemical form would each element be present?

Aadit Sharma

Numerade Educator

01:19

Problem 3

Use equations (2.10) and (2.11) to calculate $\mathrm{pK}_{\mathrm{a}}$ values for each of the cations in the previous question and determine whether any of the ions needs to be shifted to another category of acidity.

David Collins

Numerade Educator

02:10

Problem 4

For each category of metal ion listed, give a. the typical range of $Z^2 / r$ ratios found if the Pauling electronegativity of the metal is less than 1.8 ; . the typical range of $Z^2 / r$ ratios found if the Pauling electronegativity is greater than 1.8; c. the approximate $\mathrm{pH}$ range at or above which the hydroxide of the metal will precipitate; $\mathrm{d}$. two real metal ions from the $d$-block of metals that fall in that category. Categories:
4.1 Feebly acidic
4.2 Moderately acidic
4.3 Weakly acidic
4.4 Strongly acidic

Manik Pulyani

Numerade Educator

02:51

Problem 5

Describe briefly what will happen when you try to dissolve each of the following compounds in water: a. $\mathrm{KCl} ;$ b. $\mathrm{NbCl}_5$; c. $\mathrm{AlBr}_3 ;$ d. $\mathrm{CBr}_4$; e. $\mathrm{BaI}_2$; f. IF 7 . Which of these would be likely to fume in air and why?

Ronald Prasad

Numerade Educator

08:05

Problem 6

Referring to Table 2.3 , compute the smallest and the largest radius that will allow $\mathrm{a}+1$ ion to fit into each category of cation acidity; do the same for $+2,+3$, and +4 ions. Then referring to Table $\mathrm{C}$ (and the electronegativity table), list all ions from Table $\mathbf{C}$ that fit into each of the categories. Locate the ions of each category on a periodic table to see what sort of periodic pattern results.

A. Elizabeth Hildreth

Numerade Educator

05:53

Problem 7

Name each of the following oxo anions, calculate its approximate $\mathrm{pK}_{\mathrm{b} 1}$, and tell whether its solution in water will be neutral, feebly basic, moderately basic, or so strongly basic that it will react with the water to form a hydroxo anion:
a. $\mathrm{CO}_3{ }^{2-}$;
b. $\mathrm{BrO}_4^{-}$;
c. $\mathrm{IO}_6{ }^{5-}$;
d. $\mathrm{XeO}_6{ }^{4-}$;
e. $\mathrm{AsO}_3{ }^{3-}$;
f. IO

Kim Trang Nguyen

Numerade Educator

01:54

Problem 8

Write the formulas of each of the following oxo anions and classify each as nonbasic, feebly basic, moderately basic, or very strongly basic: a. silicate;
b. tellurate;
c. perbromate;
d. sulfite;
e. hypochlorite;
f. perneptunate;
g. nitrite;
h. ferrate.

Aadit Sharma

Numerade Educator

00:43

Problem 9

Write the formula (including charge) of the oxo anion of a. boron with oxidation number +3 , and $\mathbf{b}$. bromine with oxidation number +3 .

Sam Limsuwannarot

Numerade Educator

01:06

Problem 10

Without using equation (2.14), cancel oxo groups and negative charges to select the appropriate category of basicity for each of the following hypothetical oxo anions: a. $\mathrm{MO}_5^{2-}$;
b. $\mathrm{MO}_5{ }^{5-}$;
c. $\mathrm{MO}_7{ }^{6-}$. List them in order of increasing basicity.

Sima Sarker

Numerade Educator

02:10

Problem 11

Name each of the following salts: a. $\mathrm{UO}_2 \mathrm{SO}_4$;
b. $\mathrm{TiCl}_3$;
c. $\mathrm{SO}_2 \mathrm{Cl}_2$;
d. $\mathrm{FePO}_4$;
e. $\mathrm{Ag}_5 \mathrm{IO}_6$;
f. $\mathrm{Hg}_3 \mathrm{TeO}_6$.

Catherine Lemar

Numerade Educator

03:59

Problem 12

Give the formulas of the following salts: $\mathbf{a}$. bismuthyl nitrate;
b. strontium perchlorate;
c. europium(II) sulfite;
d. iron(II) phosphate;
e. chromium(II) carbonate;
f. cesium phosphate;
g. zinc(II) perbromate;
h. potassium perbromate;
i. calcium bromite;
j. calcium borate.

William Braaton

Numerade Educator

08:06

Problem 13

Explain how and why the basicity of an oxo anion depends on its charge, the number of oxo groups present, and the electronegativity. Use your reasoning to try to predict the approximate basicity of the following more complicated oxo anions: $\left(\mathrm{O}_3 \mathrm{P}-\mathrm{O}-\mathrm{PO}_3\right)^{4-}$ (pyrophosphate ion); $\left(\mathrm{O}_3 \mathrm{P}-\mathrm{O}-\mathrm{PO}_2-\mathrm{O}-\mathrm{PO}_3\right)^{5-}$ (tripolyphosphate ion).

Kim Trang Nguyen

Numerade Educator

01:49

Problem 14

When the use of tripolyphosphates in detergents was under attack, sodium carbonate and sodium silicate were tried as replacements for use in high concentration in detergents. But concern was expressed that such detergents would be very dangerous if infants swallowed them, and might also be quite corrosive to the washing machines. Explain why.

David Collins

Numerade Educator

00:33

Problem 15

Calculate the expected $\mathrm{pK}_{\mathrm{b} 1}$ 's of the following oxo anions, which are hypothetical or quite unstable. $\mathrm{a} . \mathrm{BrO}_2^{-}$;
b. $\mathrm{MnO}_4^{3-}$;
c. $\mathrm{UO}_4{ }^{2-}$.

David Collins

Numerade Educator

04:44

Problem 16

Write the formula of each of the following oxo acids and tell whether its solution in water will be very strongly acidic, strongly acidic, moderately acidic, or weakly acidic: a. permanganic acid;
b. selenic acid;
c. arsenious acid;
d. selenous acid;
e. telluric acid:
f. molybdic acid.

Grigoriy Sereda

Numerade Educator

01:13

Problem 17

For each of the following elements, give its expected oxidation number, and give the formula of the form (species) in which you would expect to find it in water of $\mathrm{pH} 5.5$ to 7. a. $\mathrm{Li} ; \mathbf{b}$. Al; c. W. Referring to your answers to questions 13.3 and 13.4 in Chapter 1, do the same for the following: d. element number 121; e. Rn; and the elements directly below f. Np;g. No; h. Os; i. Pb.

Nicole Smina

Numerade Educator

02:55

Problem 18

A lake near the Oak Ridge National Laboratory in Tennessee has become contaminated with plutonium from the reprocessing of spent fuel from nuclear reactors. Predict whether most of the plutonium in this lake is likely to be dissolved in the water or will be found in the sediments at the bottom of the lake. Also predict whether this situation might be altered if the lake were strongly subjected to the effects of acid rain.

David Collins

Numerade Educator

02:25

Problem 19

Two radioactive elements, technetium (Tc, no, 43) and promethium (Pm, no. 61) do not occur naturally on earth but are found in the fallout from atomic bomb explosions. Predict the formulas of the forms (cation, anion, or oxide) in which each would likely be found in a lake of $\mathrm{pH} 5.5$ to 7 .

Ronald Prasad

Numerade Educator

03:25

Problem 20

Which of the following hydrated metal ions would you expect to be colored? $\mathrm{Bi}^{3+}, \mathrm{Rb}^{+}, \mathrm{Tl}^{+}, \mathrm{Cr}^{2+}, \mathrm{Dy}^{3+}, \mathrm{Ce}^{4+}$.

Cameron Oden

Numerade Educator

01:36

Problem 21

If you did not do Experiments 1 and 2, go back and try to apply the principles of this chapter to predict what would have happened in each experiment. Also answer the questions included in each experiment.

Allison Knapp

Numerade Educator