Chapter 4

The solubility of magnesium hydroxide, \(\mathrm{Mg}(\mathrm{OH})_{2},\) in water is \(9.0 \times 10^{-4} \mathrm{g} / 100.0 \mathrm{mL} .\) What volume of \(0.00100 M \mathrm{HNO}_{3}\) is required to neutralize \(1.00 \mathrm{L}\) of saturated \(\mathrm{Mg}(\mathrm{OH})_{2}\) solution?

What is the difference between a saturated solution and a supersaturated solution?

What are common solubility units?

A precipitate may appear when two completely clear aqueous solutions are mixed. What circumstances are responsible for this event?

Is a saturated solution always a concentrated solution? Explain.

Behavior of Honey Honey is a concentrated solution of sugar molecules in water. Clear, viscous honey becomes cloudy after being stored for long periods. Explain how this transition illustrates supersaturation.

According to the solubility rules in Table 4.4 and Table 4.5 which of the following compounds have limited solubility in water? (a) barium sulfate; (b) barium hydroxide; (c) lanthanum nitrate; (d) sodium acetate; (e) lead hydroxide; (f) calcium phosphate

Complete and balance the molecular equations for the precipitation reactions, if any, between the following pairs of reactants, and write the overall and net ionic equations. a. \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{Na}_{2} \mathrm{SO}_{4}(a q) \rightarrow\) b. \(\mathrm{NiCl}_{2}(a q)+\mathrm{NH}_{4} \mathrm{NO}_{3}(a q) \rightarrow\) c. \(\operatorname{Fe} C l_{2}(a q)+N a_{2} S(a q) \rightarrow\) d. \(\operatorname{MgSO}_{4}(a q)+\mathrm{BaCl}_{2}(a q) \rightarrow\)

Wastewater Treatment Show with appropriate net ionic equations how \(\mathrm{Cr}^{3+}\) and \(\mathrm{Cd}^{2+}\) can be removed from wastewater by treatment with solutions of sodium hydroxide.

Calculate the mass of \(\mathrm{MgCO}_{3}\) precipitated by mixing \(10.0 \mathrm{mL}\) of a \(0.200 M \mathrm{Na}_{2} \mathrm{CO}_{3}\) solution with \(5.00 \mathrm{mL}\) of \(0.0500 M \mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}\) solution.

Toxic chromate can be precipitated from an aqueous solution by bubbling \(\mathrm{SO}_{2}\) through the solution. How many grams of \(\mathrm{SO}_{2}\) are required to treat \(3.0 \times 10^{8} \mathrm{L}\) of \(0.050 \mathrm{mM} \mathrm{CrO}_{4}^{-} ?\) $$\begin{aligned} &2 \mathrm{CrO}_{4}^{2-}(a q)+3 \mathrm{SO}_{2}(g)+4 \mathrm{H}^{+}(a q) \rightarrow\\\ &\mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}(s)+2 \mathrm{H}_{2} \mathrm{O}(\ell) \end{aligned}$$

Iron(II) can be precipitated from a slightly basic aqueous solution by bubbling oxygen through the solution, which converts soluble \(\mathrm{Fe}(\mathrm{OH})^{+}\) to insoluble \(\mathrm{Fe}(\mathrm{OH})_{3} .\) How many grams of \(\mathrm{O}_{2}\) are consumed to precipitate all of the iron in \(75 \mathrm{mL}\) of \(0.090 M\) iron(II)? \(4 \mathrm{Fe}(\mathrm{OH})^{+}(a q)+4 \mathrm{OH}^{-}(a q)+\mathrm{O}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) $$4 \mathrm{Fe}(\mathrm{OH})_{3}(s)$$

Given the following equation, how many grams of \(\mathrm{PbCO}_{3}\) will dissolve when \(1.00 \mathrm{L}\) of \(1.00 \mathrm{M} \mathrm{H}^{+}\) is added to \(5.00 \mathrm{g}\) of $\mathrm{PbCO}_{3} ?$$$ \mathrm{PbCO}_{3}(s)+2 \mathrm{H}^{+}(a q) \rightarrow \mathrm{Pb}^{2+}(a q)+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(g)$$

Treating Drinking Water Phosphate can be removed from drinking-water supplies by treating the water with \(\mathrm{Ca}(\overline{\mathrm{OH}})_{2} .\) How much \(\mathrm{Ca}(\mathrm{OH})_{2}\) is required to remove \(90 \%\) of the \(\mathrm{PO}_{4}^{3-}\) from \(4.5 \times 10^{6} \mathrm{L}\) of drinking water containing \(25 \mathrm{mg} / \mathrm{L}\) of \(\mathrm{PO}_{4}^{3-} ?\) \(5 \mathrm{Ca}(\mathrm{OH})_{2}(a q)+3 \mathrm{PO}_{4}^{3-}(a q) \rightarrow \mathrm{Ca}_{5} \mathrm{OH}\left(\mathrm{PO}_{4}\right)_{3}(s)+9 \mathrm{OH}^{-}(a q)\)

Toxic cyanide ions can be removed from wastewater by adding hypochlorite. \(2 \mathrm{CN}^{-}(a q)+5 \mathrm{OCl}^{-}(a q)+\mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) $$ \mathrm{N}_{2}(g)+2 \mathrm{HCO}_{3}^{-}(a q)+5 \mathrm{Cl}^{-}(a q) $$ a. If \(1.50 \times 10^{3} \mathrm{L}\) of \(0.125 M \mathrm{OCl}^{-}\) are required to remove the \(\mathrm{CN}^{-}\) in \(3.4 \times 10^{6} \mathrm{L}\) of wastewater, what is the \(\mathrm{CN}^{-}\) concentration in the water in \(\mathrm{mg} / \mathrm{L} ?\) "b. How many milliliters of \(0.575 \mathrm{M} \mathrm{Ag} \mathrm{NO}_{3}\) would you need to add to a \(50.00 \mathrm{mL}\) aliquot of the final solution (consider the volumes simply additive) to precipitate the chloride ions formed in the reaction?

For each of the following aqueous mixtures, determine which ionic concentrations decrease and which remain the same. a. Sodium chloride and silver nitrate are dissolved in \(100 \mathrm{mL}\) of water. b. Equimolar amounts of sodium hydroxide and hydrochloric acid react. c. Ammonium sulfate and potassium bromide are dissolved in 100 mL of water.

For each of the following aqueous mixtures, determine which ionic concentrations decrease and which remain the same. a. Sodium chloride and iron(II) chloride are dissolved in \(100 \mathrm{mL}\) of water. b. Equimolar amounts of sodium carbonate and sulfuric acid react. c. Potassium sulfate and barium nitrate are dissolved in \(100 \mathrm{mL}\) of water.

Explain how a mixture of anion and cation exchangers can be used to deionize water.

Describe the process by which the ion exchanger in a home water softener is regenerated for further use.

(a) Use the solubility rules to write the balanced net ionic equation for each of the following "molecular" reactions. If there is no net reaction, write "NR." (b) Which of these three reactions give clear visual evidence of the ion exchange process? 1\. \(\mathrm{NaCl}(a q)+\mathrm{AgNO}_{3}(a q) \rightarrow \mathrm{AgCl}(s)+\mathrm{NaNO}_{3}(a q)\) 2\. \(\mathrm{NaCl}(a q)+\mathrm{KNO}_{3}(a q) \rightarrow \mathrm{NaNO}_{3}(a q)+\mathrm{KCl}(a q)\) 3\. \(\operatorname{MgCl}_{2}(a q)+\mathrm{KOH}(a q) \rightarrow \mathrm{Mg}(\mathrm{OH})_{2}(s)+\mathrm{KCl}(a q)\)

(a) Use the solubility rules to write the balanced net ionic equation for each of the following "molecular" reactions. If there is no net reaction, write "NR." (b) Which of these three reactions give clear visual evidence of the ion exchange process? 1\. \(\mathrm{BaCl}_{2}(a q)+\mathrm{Na}_{2} \mathrm{CO}_{3}(a q) \rightarrow \mathrm{BaCO}_{3}(s)+\mathrm{NaCl}(a q)\) 2\. \(\mathrm{NaCl}(a q)+\mathrm{KOH}(a q) \rightarrow \mathrm{NaOH}(a q)+\mathrm{KCl}(a q)\) 3\. \(\mathrm{Na}_{3} \mathrm{PO}_{4}(a q)+\mathrm{CaCl}_{2}(a q) \rightarrow \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)+\mathrm{NaCl}(a q)\)

How are the gains or losses of electrons related to changes in oxidation numbers?

What is the sum of the oxidation numbers of the atoms in a molecule?

Gold does not dissolve in concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) but readily dissolves in \(\mathrm{H}_{2} \mathrm{SeO}_{4}\) (selenic acid). Which acid is the stronger oxidizing agent?

Silver dissolves in sulfuric acid to form silver sulfate and \(\mathrm{H}_{2},\) but gold does not dissolve in sulfuric acid to form gold sulfate. Which of the two metals is the better reducing agent?

What is meant by a half-reaction?

What are the half-reactions that take place in the electrolysis of molten \(\mathrm{NaCl}\) ?

Electron gain is associated with _______ half-reactions, and electron loss is associated with ______ half-reactions.

Give the oxidation number of boron in each of the following: (a) \(\mathrm{HBO}_{2}\) (metaboric acid); (b) \(\mathrm{H}_{3} \mathrm{BO}_{3}\) (boric acid); (c) \(\mathrm{Na}_{2} \mathrm{B}_{4} \mathrm{O}_{7}\) (sodium borate).

Give the oxidation number of nitrogen in each of the following: (a) elemental nitrogen \(\left(\mathrm{N}_{2}\right) ;\) (b) hydrazine \(\left(\mathrm{N}_{2} \mathrm{H}_{4}\right) ;(\mathrm{c})\) ammonium ion \(\left(\mathrm{NH}_{4}^{+}\right)\)

Balance the following half-reactions by adding the appropriate number of electrons. Identify the oxidation half-reactions and the reduction half- reactions. a. \(\operatorname{Br}_{2}(\ell) \rightarrow 2 \operatorname{Br}^{-}(a q)\) b. \(\mathrm{Pb}(s)+2 \mathrm{Cl}^{-}(a q) \rightarrow \mathrm{PbCl}_{2}(s)\) c. \(\mathrm{O}_{3}(g)+2 \mathrm{H}^{+}(a q) \rightarrow \mathrm{O}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(\ell)\) d. \(2 \mathrm{H}_{2} \mathrm{SO}_{3}(a q)+\mathrm{H}^{+}(a q) \rightarrow \mathrm{HS}_{2} \mathrm{O}_{4}^{-}(a q)+2 \mathrm{H}_{2} \mathrm{O}(\ell)\)

Balance the following half-reactions by adding the appropriate number of electrons. Which are oxidation half-reactions and which are reduction half- reactions? a. \(\mathrm{Fe}^{2+}(a q) \rightarrow \mathrm{Fe}^{3+}(a q)\) b. \(\operatorname{Ag}\left[(s) \rightarrow \operatorname{Ag}(s)+\bar{I}^{-}(a q)\right.\) c. \(\mathrm{VO}_{2}^{+}(a q)+2 \mathrm{H}^{+}(a q) \rightarrow \mathrm{VO}^{2+}(a q)+\mathrm{H}_{2} \mathrm{O}(\ell)\) d. \(\mathrm{I}_{2}(s)+6 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow 2 \mathrm{IO}_{3}^{-}(a q)+12 \mathrm{H}^{+}(a q)\)

Balance the following net ionic reactions, and identify which elements are oxidized and which are reduced: a. \(\mathrm{MnO}_{2}(s)+\mathrm{HCl}(a q) \rightarrow \mathrm{Mn}^{2+}(a q)+\mathrm{Cl}_{2}(g)\) b. \(\mathrm{I}_{2}(s)+\mathrm{S}_{2} \mathrm{O}_{3}^{2-}(a q) \rightarrow \mathrm{S}_{4} \mathrm{O}_{6}^{2-}(a q)+\mathrm{I}^{-}(a q)\) c. \(\mathrm{MnO}_{4}^{-}(a q)+\mathrm{Fe}^{2+}(a q) \rightarrow \mathrm{Mn}^{2+}(a q)+\mathrm{Fe}^{3+}(a q)\)

Balance the following net ionic reactions, and identify which elements are oxidized and which are reduced: a. \(\mathrm{MnO}_{4}^{-}(a q)+\mathrm{S}^{2-}(a q) \rightarrow \mathrm{MnO}_{2}(s)+\mathrm{S}(s)\) b. \(\mathrm{IO}_{3}^{-}(a q)+\mathrm{I}^{-}(a q) \rightarrow \mathrm{I}_{2}(s)\) c. \(\mathrm{Mn}^{2+}(a q)+\mathrm{BiO}_{3}^{-}(a q) \rightarrow \mathrm{MnO}_{4}^{-}(a q)+\mathrm{Bi}^{3+}(a q)\)

Earth's Crust The following chemical reactions have helped to shape Earth's crust. Determine the oxidation numbers of all the elements in the reactants and products, and identify which elements are oxidized and which are reduced. a. \(3 \mathrm{SiO}_{2}(s)+2 \mathrm{Fe}_{3} \mathrm{O}_{4}(s) \rightarrow 3 \mathrm{Fe}_{2} \mathrm{SiO}_{4}(s)+\mathrm{O}_{2}(g)\) b. \(\operatorname{SiO}_{2}(s)+2 \operatorname{Fe}(s)+\mathrm{O}_{2}(g) \rightarrow \mathrm{Fe}_{2} \mathrm{SiO}_{4}(s)\) c. \(4 \mathrm{FeO}(s)+\mathrm{O}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow 4 \mathrm{Fe}(\mathrm{OH})_{3}(s)\)

Determine the oxidation numbers of each of the elements in the following reactions, and identify which of them are oxidized or reduced, if any. a. \(\operatorname{SiO}_{2}(s)+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow \mathrm{H}_{4} \mathrm{SiO}_{4}(a q)\) b. \(2 \mathrm{MnCO}_{3}(s)+\mathrm{O}_{2}(g) \rightarrow 2 \mathrm{MnO}_{2}(s)+2 \mathrm{CO}_{2}(g)\) c. \(3 \mathrm{NO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) \(2 \mathrm{NO}_{3}^{-}(a q)+\mathrm{NO}(g)+2 \mathrm{H}^{+}(a q)\)

Combine the half-reaction for the reduction of \(\mathrm{O}_{2}\) \(\mathrm{O}_{2}(a q)+4 \mathrm{H}^{+}(a q)+4 \mathrm{e}^{-} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}(\ell)\) with the following oxidation half-reactions (which are based on common iron minerals) to develop complete redox reactions: a. \(2 \mathrm{FeCO}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) \(\mathrm{Fe}_{2} \mathrm{O}_{3}(s)+2 \mathrm{CO}_{2}(g)+2 \mathrm{H}^{+}(a q)+2 \mathrm{e}^{-}\) b. \(3 \mathrm{FeCO}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) \(\mathrm{Fe}_{3} \mathrm{O}_{4}(s)+3 \mathrm{CO}_{2}(g)+2 \mathrm{H}^{+}(a q)+2 \mathrm{e}^{-}\) c. \(2 \mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow 3 \mathrm{Fe}_{2} \mathrm{O}_{3}(s)+2 \mathrm{H}^{+}(a q)+2 \mathrm{e}^{-}\)

When Soil Smells Bad In sediments and waterlogged soil, dissolved \(\mathrm{O}_{2}\) concentrations are so low that the microorganisms living there must rely on other sources of oxygen for respiration. Some bacteria can extract the oxygen from sulfate ions, reducing the sulfur in them to hydrogen sulfide gas and giving the sediments or soil a distinctive rotten-egg odor. a. What is the change in oxidation state of sulfur as a result of this reaction? b. Write the balanced net ionic equation for the reaction, under acidic conditions, that releases \(\mathrm{O}_{2}\) from sulfate and forms hydrogen sulfide gas.

Chromium is more toxic and more soluble in natural waters as \(\mathrm{HCrO}_{4}^{-}\) than as chromium(III) ion. In the presence of \(\mathrm{H}_{2} \mathrm{S}\), the following reaction takes place in neutral solution: $$ \mathrm{HCrO}_{4}^{-}(a q)+\mathrm{H}_{2} \mathrm{S}(a q) \rightarrow \mathrm{Cr}_{2} \mathrm{O}_{3}(s)+\mathrm{SO}_{4}^{2-} $$ a. Assign oxidation numbers to the reactants and products. b. Balance the equation. c. How many electrons are transferred for each atom of chromium that reacts?

The water-soluble uranyl cation, \(\mathrm{UO}_{2}^{+}\), can be removed by reaction with methane gas: $$ \mathrm{UO}_{2}^{+}(a q)+\mathrm{CH}_{4}(g) \rightarrow \mathrm{UO}_{2}(s)+\mathrm{HCO}_{3}^{-}(a q) $$ a. Assign oxidation numbers to the reactants and products. b. Balance the equation in acidic solution. c. How many electrons are transferred for each atom of uranium that reacts?

The solubilities of Fe and Mn in freshwater streams are affected by changes in their oxidation states. Complete and balance the following redox equation in which soluble \(\mathrm{Mn}^{2+}\) becomes solid MnO \(_{2}\) \(\mathrm{Fe}(\mathrm{OH})_{2}+(a q)+\mathrm{Mn}^{2+}(a q) \rightarrow \mathrm{MnO}_{2}(s)+\mathrm{Fe}^{2+}(a q)\)

Bactericide and Virucide The water-soluble gas \(\mathrm{ClO}_{2}\) is known as an oxidative biocide. It destroys bacteria by oxidizing their cell walls and destroys viruses by attacking their viral envelopes. \(\mathrm{ClO}_{2}\) may be prepared for use as a decontaminating agent from several different starting materials in slightly acidic solutions. Complete and balance the following chemical equations for the synthesis of \(\mathrm{ClO}_{2}\) a. \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{SO}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{SO}_{4}^{2-}(a q)\) b. \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{Cl}_{2}(g)\) c. \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g)\)

Which ions will oxidize aluminum? \(\mathrm{Li}^{+} ; \mathrm{Ca}^{2+} ; \mathrm{Ag}^{+} ; \mathrm{Sn}^{2+}\)

Ozone, \(\mathrm{O}_{3},\) reacts with iodide ion \(\left(\mathrm{I}^{-}\right)\) in basic solution to form \(\mathrm{O}_{2}\) and \(\mathrm{I}_{2}\) by the unbalanced chemical equation: $$ \mathrm{O}_{3}(a q)+\mathrm{I}^{-}(a q) \rightarrow \mathrm{O}_{2}(g)+\mathrm{I}_{2}(a q) $$ a. Balance the equation. b. A saturated solution of ozone in \(125 \mathrm{mL}\) of water at \(0^{\circ} \mathrm{C}\) is treated with \(10 \mathrm{mL}\) of \(2.0 \mathrm{MKI}\). After the reaction is complete, the solution is titrated with \(0.100 M \mathrm{H}^{+} .\) If \(54.7 \mathrm{mL}\) of acid is needed, what is the concentration of \(\mathrm{O}_{3}\) in a saturated solution?

A puddle of coastal seawater, caught in a depression formed by some coastal rocks at high tide, begins to evaporate on a hot summer day as the tide goes out. If the volume of the puddle decreases to \(23 \%\) of its initial volume, what is the concentration of \(\mathrm{Na}^{+}\) after evaporation if initially it was \(0.449 M ?\)

Antifreeze Ethylene glycol is the common name for the liquid used to keep the coolant in automobile cooling systems from freezing. It is \(38.7 \%\) carbon, \(9.7 \%\) hydrogen, and \(51.6 \%\) oxygen by mass. Its molar mass is \(62.07 \mathrm{g} / \mathrm{mol}\) and its density is \(1.106 \mathrm{g} / \mathrm{mL}\) at \(20^{\circ} \mathrm{C}\) a. What is the empirical formula of ethylene glycol? b. What is the molecular formula of ethylene glycol? c. In a solution prepared by mixing equal volumes of water and ethylene glycol, which ingredient is the solute and which is the solvent?

According to the label on a bottle of concentrated hydrochloric acid, the contents are \(36.0 \%\) HCl by mass and have a density of \(1.18 \mathrm{g} / \mathrm{mL}\) a. What is the molarity of concentrated HCl? b. What volume of it would you need to prepare \(0.250 \mathrm{L}\) of \(2.00 \mathrm{M} \mathrm{HCl}^{2}\) c. What mass of sodium hydrogen carbonate would be needed to neutralize the spill if a bottle containing 1.75 L of concentrated HCl dropped on a lab floor and broke open?

Synthesis and Toxicity of Chlorine Chlorine was first prepared in 1774 by heating a mixture of \(\mathrm{NaCl}\) and \(\mathrm{MnO}_{2}\) in sulfuric acid: \(\mathrm{NaCl}(a q)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q)+\mathrm{MnO}_{2}(s) \rightarrow\) $$ \mathrm{Na}_{2} \mathrm{SO}_{4}(a q)+\mathrm{MnCl}_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Cl}_{2}(g) $$ a. Assign oxidation numbers to the elements in each compound, and balance the redox reaction in acid solution. b. Write a net ionic equation describing the reaction for formation of chlorine. c. If chlorine gas is inhaled, it causes pulmonary edema (fluid in the lungs) because it reacts with water in the alveolar sacs of the lungs to produce the strong acid HCl and the weaker acid HOCl. Balance the equation for the conversion of \(\mathrm{Cl}_{2}\) to \(\mathrm{HCl}\) and \(\mathrm{HOCl}\).

When a solution of dithionate ions \(\left(\mathrm{S}_{2} \mathrm{O}_{4}^{2-}\right)\) is added to a solution of chromate ions \(\left(\mathrm{CrO}_{4}^{2-}\right),\) the products of the reaction under basic conditions include soluble sulfite ions and solid chromium(III) hydroxide. This reaction is used to remove chromium(VI) from wastewater generated by factories that make chrome-plated metals. a. Write the net ionic equation for this redox reaction. b. Which element is oxidized and which is reduced? c. Identify the oxidizing and reducing agents in this reaction. d. How many grams of sodium dithionate would be needed to remove the chromium(VI) in \(100.0 \mathrm{L}\) of wastewater that contains \(0.00148 M\) chromate ion?

Polishing Silver Silver tarnish is the result of silver metal reacting with sulfur compounds, such as \(\mathrm{H}_{2} \mathrm{S}\), in the air. The tarnish on silverware \(\left(\mathrm{Ag}_{2} \mathrm{S}\right)\) can be removed by soaking in a solution of \(\mathrm{NaHCO}_{3}\) (baking soda) in a basin lined with aluminum foil. a. Write a balanced equation for the tarnishing of Ag to \(\mathrm{Ag}_{2} \mathrm{S},\) and assign oxidation numbers to the reactants and products. How many electrons are transferred per mole of silver? b. Write a balanced equation for the reaction of \(\mathrm{Ag}_{2} \mathrm{S}\) with Al metal, NaHCO \(_{3},\) and water to produce Al(OH) \(_{3}\) \(\mathrm{H}_{2} \mathrm{S}, \mathrm{H}_{2},\) and \(\mathrm{Ag}\) metal.