Chapter 5

What is an electrolyte? How can you differentiate experimentally between a weak electrolyte and a strong electrolyte? Give an example of each.

Name two acids that are strong electrolytes and one acid that is a weak electrolyte. Name two bases that are strong electrolytes and one base that is a weak electrolyte.

Which compound or compounds in each of the following groups is (are) expected to be soluble in water? (a) \(\mathrm{CuO}, \mathrm{CuCl}_{2}, \mathrm{FeCO}_{3}\) (b) \(\mathrm{AgI}, \mathrm{Ag}_{3} \mathrm{PO}_{4}, \mathrm{AgNO}_{3}\) (c) \(\mathrm{K}_{2} \mathrm{CO}_{3}, \mathrm{KI}, \mathrm{KMnO}_{4}\)

Which compound or compounds in each of the following groups is (are) expected to be soluble in water? (a) \(\mathrm{BaSO}_{4}, \mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}, \mathrm{BaCO}_{3}\) (b) \(\mathrm{Na}_{2} \mathrm{SO}_{4}, \mathrm{NaClO}_{4}, \mathrm{NaCH}_{3} \mathrm{CO}_{2}\) (c) \(\mathrm{AgBr}, \mathrm{KBr}, \mathrm{Al}_{2} \mathrm{Br}_{6}\)

The following compounds are water-soluble. What ions are produced by each compound in aqueous solution? (a) KOH (c) \(\mathrm{LiNO}_{3}\) (b) \(\mathrm{K}_{2} \mathrm{SO}_{4}\) (d) \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}\)

The following compounds are water-soluble. What ions are produced by each compound in aqueous solution? (a) \(\mathrm{KI}\) (c) \(\mathrm{K}_{2} \mathrm{HPO}_{4}\) (b) \(\mathrm{Mg}\left(\mathrm{CH}_{3} \mathrm{CO}_{2}\right)_{2}\) (d) NaCN

Decide whether each of the following is water-soluble. If soluble, tell what ions are produced. (a) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (c) NiS (b) \(\mathrm{CuSO}_{4}\) (d) \(\mathrm{BaBr}_{2}\)

Decide whether each of the following is water-soluble. If soluble, tell what ions are produced. (a) \(\mathrm{NiCl}_{2}\) (c) \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}\) (b) \(\mathrm{Cr}\left(\mathrm{NO}_{3}\right)_{3}\) (d) \(\mathrm{BaSO}_{4}\)

Balance the equation for the following precipitation reaction, and then write the net ionic equation. Indicate the state of each species \((s, \ell, \text { aq, or } g\) ). $$\mathrm{CdCl}_{2}+\mathrm{NaOH} \longrightarrow \mathrm{Cd}(\mathrm{OH})_{2}+\mathrm{NaCl}$$

Balance the equation for the following precipitation reaction, and then write the net ionic equation. Indicate the state of each species (s, \(\ell\), aq, or g). $$\mathrm{Ni}\left(\mathrm{NO}_{3}\right)_{2}+\mathrm{Na}_{2} \mathrm{CO}_{3} \longrightarrow \mathrm{NiCO}_{3}+\mathrm{NaNO}_{3}$$

Predict the products of each precipitation reaction. Balance the completed equation, and then write the net ionic equation. (a) \(\mathrm{NiCl}_{2}(\mathrm{aq})+\left(\mathrm{NH}_{1}\right)_{2} \mathrm{S}(\mathrm{aq}) \longrightarrow ?\) (b) \(\operatorname{Mn}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{Na}_{3} \mathrm{PO}_{4}(\mathrm{aq}) \longrightarrow ?\)

Predict the products of each precipitation reaction. Balance the completed equation, and then write the net ionic equation. (a) \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{KBr}(\mathrm{aq}) \longrightarrow ?\) (b) \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{KF}(\mathrm{aq}) \longrightarrow ?\) (c) \(\operatorname{Ca}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq}) \longrightarrow ?\)

Write a balanced equation for the ionization of nitric acid in water.

Write a balanced equation for the ionization of perchloric acid in water.

Oxalic acid, \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4},\) which is found in certain plants, can provide two hydrogen ions in water. Write balanced equations (like those for sulfuric acid on page 186 ) to show how oxalic acid can supply one and then a second \(\mathrm{H}^{+}\) ion.

Phosphoric acid can supply one, two, or three \(\mathrm{H}^{+}\) ions in aqueous solution. Write balanced equations (like those for sulfuric acid on page 186 ) to show this successive loss of hydrogen ions.

Write a balanced equation for reaction of the basic oxide, magnesium oxide, with water.

Complete and balance the following acid-base reactions. Name the reactants and products. (a) \(\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}(\mathrm{aq})+\mathrm{Mg}(\mathrm{OH})_{2}(\mathrm{s}) \longrightarrow\) (b) \(\mathrm{HClO}_{4}(\mathrm{aq})+\mathrm{NH}_{3}(\mathrm{aq}) \longrightarrow\)

Complete and balance the following acid-base reactions. Name the reactants and products. (a) \(\mathrm{H}_{3} \mathrm{PO}_{4}(\mathrm{aq})+\mathrm{KOH}(\mathrm{aq}) \longrightarrow\) (b) \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+\mathrm{Ca}(\mathrm{OH})_{2}(\mathrm{s}) \longrightarrow\) $$\left(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\right.$$ is oxalic acid, an acid capable of donating two $$\left.\mathrm{H}^{+} \text {ions. }\right)$$

Write a balanced equation for the reaction of barium hydroxide with nitric acid.

Write a balanced equation for the reaction of aluminum hydroxide with sulfuric acid.

Balance the following equations, and then write the net ionic equation. (a) \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}(\mathrm{aq})+\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq}) \longrightarrow\) \(\mathrm{CuCO}_{3}(\mathrm{s})+\mathrm{NH}_{4} \mathrm{NO}_{3}(\mathrm{aq})\) (b) \(\mathrm{Pb}(\mathrm{OH})_{2}(\mathrm{s})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow \mathrm{PbCl}_{2}(\mathrm{s})+\mathrm{H}_{2} \mathrm{O}(\ell)\) (c) \(\mathrm{BaCO}_{3}(\mathrm{s})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow\) \(\mathrm{BaCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})\)

Balance the following equations, and then write the net ionic equation: (a) \(\mathrm{Zn}(\mathrm{s})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow \mathrm{H}_{2}(\mathrm{g})+\mathrm{ZnCl}_{2}(\mathrm{aq})\) (b) \(\mathrm{Mg}(\mathrm{OH})_{2}(\mathrm{s})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow \mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)\) (c) \(\mathrm{HNO}_{3}(\mathrm{aq})+\mathrm{CaCO}_{3}(\mathrm{s}) \longrightarrow\) \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})\)

Balance the following equations, and then write the net ionic equation. Show states for all reactants and products \((s, \ell, g, a q)\) (a) the reaction of silver nitrate and potassium iodide to give silver iodide and potassium nitrate (b) the reaction of barium hydroxide and nitric acid to give barium nitrate and water (c) the reaction of sodium phosphate and nickel(II) nitrate to give nickel(11) phosphate and sodium nitrate

Balance each of the following equations, and then write the net ionic equation. Show states for all reactants and products \((\mathrm{s}, \ell, \mathrm{g}, \mathrm{aq})\) (a) the reaction of sodium hydroxide and iron (II) chloride to give iron(II) hydroxide and sodium chloride (b) the reaction of barium chloride with sodium carbonate to give barium carbonate and sodium chloride

Balance the following reactions and then classify each as a precipitation, acid-base, or gas-forming reaction. (a) \(\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow \mathrm{BaCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)\) (b) \(\mathrm{HNO}_{3}(\mathrm{aq})+\mathrm{CoCO}_{3}(\mathrm{s}) \longrightarrow\) \(\operatorname{Co}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})\) (c) \(\mathrm{Na}_{3} \mathrm{PO}_{4}(\mathrm{aq})+\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq}) \longrightarrow\) \(\mathrm{Cu}_{3}\left(\mathrm{PO}_{4}\right)_{2}(\mathrm{s})+\mathrm{NaNO}_{3}(\mathrm{aq})\)

Balance the following reactions and then classify each as a precipitation, acid-base reaction, or a gas-forming reaction. (a) \(\mathrm{K}_{2} \mathrm{CO}_{3}(\mathrm{aq})+\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq}) \longrightarrow\) \(\mathrm{CuCO}_{3}(\mathrm{s})+\mathrm{KNO}_{3}(\mathrm{aq})\) (b) \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow \mathrm{PbCl}_{2}(\mathrm{s})+\mathrm{HNO}_{3}(\mathrm{aq})\) (c) \(\mathrm{MgCO}_{3}(\mathrm{s})+\mathrm{HCl}(\mathrm{aq}) \longrightarrow\) \(\mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})\)

Balance the following reactions and then classify each as a precipitation, acid-base reaction, or gas-forming reaction. Show states for the products (s, \(\ell, g,\) aq) and then balance the completed equation. Write the net ionic equation. (a) \(\mathrm{MnCl}_{2}(\mathrm{aq})+\mathrm{Na}_{2} \mathrm{S}(\mathrm{aq}) \longrightarrow \mathrm{MnS}+\mathrm{NaCl}\) (b) \(\mathrm{K}_{2} \mathrm{CO}_{3}(\mathrm{aq})+\mathrm{ZnCl}_{2}(\mathrm{aq}) \longrightarrow \mathrm{ZnCO}_{3}+\mathrm{KCl}\)

Balance the following reactions and then classify each as a precipitation, acid-base, or gas-forming reaction. Write the net ionic equation. (a) \(\mathrm{Fe}(\mathrm{OH})_{3}(\mathrm{s})+\mathrm{HNO}_{3}(\mathrm{aq}) \longrightarrow \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}+\mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{FeCO}_{3}(\mathrm{s})+\mathrm{HNO}_{3}(\mathrm{aq}) \longrightarrow \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}+\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O}\)

What feature causes the following reactions to be product-favored? (a) \(\mathrm{CuCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{S}(\mathrm{aq}) \longrightarrow \mathrm{CuS}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq})\) (b) \(\mathrm{H}_{3} \mathrm{PO}_{4}(\mathrm{aq})+3 \mathrm{KOH}(\mathrm{aq}) \longrightarrow 3 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{K}_{3} \mathrm{PO}_{4}(\mathrm{aq})\)

Determine the oxidation number of each element in the following ions or compounds. (a) \(\mathrm{BrO}_{3}^{-}\) (d) \(\mathrm{CaH}_{2}\) (b) \(\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\) (e) \(\mathrm{H}_{1} \mathrm{SiO}_{4}\) (c) \(\mathrm{F}^{-}\) (f) \(\mathrm{HSO}_{4}^{-}\)

Determine the oxidation number of each element in the following ions or compounds. (a) \(\mathrm{PF}_{6}^{-}\) (d) \(\mathrm{N}_{2} \mathrm{O}_{5}\) (b) \(\mathrm{H}_{2} \mathrm{AsO}_{4}^{-}\) (e) \(\mathrm{POCl}_{3}\) (c) \(\mathrm{UO}^{2+}\) (f) \(\mathrm{XeO}_{4}^{2-}\)

Which two of the following reactions are oxidation-reduction reactions? Explain your answer in each case. Classify the remaining reaction. (a) \(\mathrm{Zn}(\mathrm{s})+2 \mathrm{NO}_{3}^{-}(\mathrm{aq})+4 \mathrm{H}^{+}(\mathrm{aq}) \longrightarrow\) \(\mathrm{Zn}^{2+}(\mathrm{aq})+2 \mathrm{NO}_{2}(\mathrm{g})+2 \mathrm{H}_{2} \mathrm{O}(\ell)\) (b) \(\operatorname{Zn}(\mathrm{OH})_{2}(\mathrm{s})+\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) \longrightarrow \mathrm{ZnSO}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell)\) (c) \(\mathrm{Ca}(\mathrm{s})+2 \mathrm{H}_{2} \mathrm{O}(\ell) \longrightarrow \mathrm{Ca}(\mathrm{OH})_{2}(\mathrm{s})+\mathrm{H}_{2}(\mathrm{g})\)

Which two of the following reactions are oxidationreduction reactions? Explain your answer briefly. Classify the remaining reaction. (a) \(\operatorname{Cd} \mathrm{Cl}_{2}(\mathrm{aq})+\mathrm{Na}_{2} \mathrm{S}(\mathrm{aq}) \longrightarrow \operatorname{CdS}(\mathrm{s})+2 \mathrm{NaCl}(\mathrm{aq})\) (b) \(2 \mathrm{Ca}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{CaO}(\mathrm{s})\) (c) \(4 \mathrm{Fe}(\mathrm{OH})_{2}(\mathrm{s})+2 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow 4 \mathrm{Fe}(\mathrm{OH})_{3}(\mathrm{aq})\)

In the following reactions, decide which reactant is oxidized and which is reduced. Designate the oxidizing agent and the reducing agent. (a) \(\mathrm{C}_{2} \mathrm{H}_{4}(\mathrm{g})+3 \mathrm{O}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{CO}_{2}(\mathrm{g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})\) (b) \(\mathrm{Si}(\mathrm{s})+2 \mathrm{Cl}_{2}(\mathrm{g}) \longrightarrow \mathrm{SiCl}_{4}(\ell)\)

In the following reactions, decide which reactant is oxidized and which is reduced. Designate the oxidizing agent and the reducing agent. (a) \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(\mathrm{aq})+3 \mathrm{Sn}^{2+}(\mathrm{aq})+14 \mathrm{H}^{+}(\mathrm{aq}) \longrightarrow\) \(2 \mathrm{Cr}^{3+}(\mathrm{aq})+3 \mathrm{Sn}^{4+}(\mathrm{aq})+7 \mathrm{H}_{2} \mathrm{O}(\ell)\) (b) \(\mathrm{FeS}(\mathrm{s})+3 \mathrm{NO}_{3}^{-}(\mathrm{aq})+4 \mathrm{H}^{+}(\mathrm{aq}) \longrightarrow\) \(3 \mathrm{NO}(\mathrm{g})+\mathrm{SO}_{4}^{2-}(\mathrm{aq})+\mathrm{Fe}^{3+}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell)\)

If \(6.73 \mathrm{g}\) of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) is dissolved in enough water to make \(250 .\) mL of solution, what is the molar concentration of the sodium carbonate? What are the molar concentrations of the \(\mathrm{Na}^{+}\) and \(\mathrm{CO}_{3}^{2-}\) ions?

Some potassium dichromate \(\left(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\right), 2.335 \mathrm{g},\) is dissolved in enough water to make exactly \(500 .\) mL of solution. What is the molar concentration of the potassium dichromate? What are the molar concentrations of the \(\mathbf{K}^{+}\) and \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}\) ions?

What is the mass of solute, in grams, in \(250 .\) mL. of a \(0.0125 \mathrm{M}\) solution of \(\mathrm{KMnO}_{4} ?^{-}\)

What volume of \(0.123 \mathrm{M} \mathrm{NaOH},\) in milliliters, contains \(25.0 \mathrm{g}\) of \(\mathrm{NaOH} ?\)

What volume of \(2.06 \mathrm{M} \mathrm{KMnO}_{4},\) in liters, contains \(322 \mathrm{g}\) of solute?

For each solution, identify the ions that exist in aqueous solution, and specify the concentration of each ion. (a) \(0.25 \mathrm{M}\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}\) (b) \(0.123 \mathrm{M} \mathrm{Na}_{2} \mathrm{CO}_{3}\) (c) \(0.056 \mathrm{M} \mathrm{HNO}_{3}\)

For each solution, identify the ions that exist in aqueous solution, and specify the concentration of each ion. (a) \(0.12 \mathrm{M} \mathrm{BaCl}_{2}\) (b) \(0.0125 \mathrm{M} \mathrm{CuSO}_{4}\) (c) \(0.500 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\)

An experiment in your laboratory requires exactly \(500 . \mathrm{mL}\) of a \(0.0200 \mathrm{M}\) solution of \(\mathrm{Na}_{2} \mathrm{CO}_{3} .\) You are given solid \(\mathrm{Na}_{2} \mathrm{CO}_{3},\) distilled water, and a \(500 .\) -mL volumetric flask. Describe how to prepare the required solution.

What mass of oxalic acid, \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4},\) is required to prepare \(250 .\) mL of a solution that has a concentration of \(0.15 \mathrm{M}\) \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{D}_{4} ?\)

If you dilute \(25.0 \mathrm{mL}\) of \(1.50 \mathrm{M}\) hydrochloric acid to 500 . mL, what is the molar concentration of the dilute acid?

If \(4.00 \mathrm{mL}\) of \(0.0250 \mathrm{M} \mathrm{CuSO}_{4}\) is diluted to \(10.0 \mathrm{mL}\) with pure water, what is the molar concentration of copper(II) sulfate in the diluted solution?

Which of the following methods would you use to prepare \(1.00 \mathrm{L}\) of \(0.125 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4} ?\) (a) Dilute \(20.8 \mathrm{mL}\) of \(6.00 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}\) to a volume of \(1.00 \mathrm{L}\) (b) Add \(950 .\) mL of water to 50.0 mL. of \(3.00 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}\).

Which of the following methods would you use to prepare \(300 . \mathrm{mL}\) of \(0.500 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} ?\) (a) Add \(30.0 \mathrm{mL}\) of \(1.50 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) to \(270 .\) mL of water. (b) Dilute \(250 .\) mL of \(0.600 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) to a volume of \(300 . \mathrm{mL}\).

A table wine has a pH of \(3.40 .\) What is the hydrogen ion concentration of the wine? Is it acidic or basic?