Indicate whether each of the following statements is true or false: (b) For the reaction Fe³⁺(aq) + Co²⁺(aq) → Fe2⁺(aq) + Co³⁺(aq), Fe³⁺(aq) is the reducing agent and Co²⁺(aq) is the oxidizing agent.

Indicate whether each of the following statements is true or false: (c) If there are no changes in the oxidation state of the reactants or products of a particular reaction, that reaction is not a redox reaction.

Indicate whether each of the following statements is true or false: (a) If something is reduced, it is formally losing electrons. (b) A reducing agent gets oxidized as it reacts.

Indicate whether each of the following statements is true or false: (c) An oxidizing agent is needed to convert CO into CO₂.

For each of the following balanced oxidation–reduction reactions, (i) identify the oxidation numbers for all the elements in the reactants and products and (ii) state the total number of electrons transferred in each reaction. (a) I₂O₅(s) + 5 CO(g) → I₂(s) + 5 CO₂(g) (b) 2 Hg²⁺(aq) + N₂H₄(aq) → 2 Hg(l) + N₂(g) + 4 H⁺(aq) (c) 3 H₂S(aq) + 2 H⁺(aq) + 2 NO₃^-(aq) → 3 S(s) + 2 NO(g) + 4 H₂O(l)

For each of the following balanced oxidation–reduction reactions, (i) identify the oxidation numbers for all the elements in the reactants and products and (ii) state the total number of electrons transferred in each reaction. (a) 2 MnO₄^-(aq) + 3 S^2-(aq + 4 H₂O(l) → 3 S(s) + 2 MnO₂(s) + 8 OH^-(aq) (b) 4 H₂O₂(aq) + Cl₂O₇(g) + 2 OH^-(aq) → 2 ClO₂^-(aq) + 5 H₂O(l) + 4 O₂(g) (c) Ba²⁺(aq) + 2 OH^-(aq) + H₂O₂(aq) + 2 ClO₂(aq) → Ba(ClO₂)₂(s) + 2 H₂O(l) + O₂(g)

Indicate whether the following balanced equations involve oxidation–reduction. If they do, identify the elements that undergo changes in oxidation number. (a) PBr₃(l) + 3 H₂O(l) → H₃PO₃(aq) + 3 HBr(aq)

Indicate whether the following balanced equations involve oxidation–reduction. If they do, identify the elements that undergo changes in oxidation number. (b) NaI(aq) + 3 HOCl(aq) → NaIO₃(aq) + 3 HCl(aq) (c) 3 SO(1g) + 2 HNO₃(aq) + 2 H₂O(l) → 3 H₂SO₄(aq) + 2 NO(g)

Indicate whether the following balanced equations involve oxidation–reduction. If they do, identify the elements that undergo changes in oxidation number. (a) 2 AgNO₃(aq) + CoCl₂(aq) → 2 AgCl(s) + Co(NO₃)₂(aq)

At 900 °C, titanium tetrachloride vapor reacts with molten magnesium metal to form solid titanium metal and molten magnesium chloride. (a) Write a balanced equation for this reaction.

At 900 °C, titanium tetrachloride vapor reacts with molten magnesium metal to form solid titanium metal and molten magnesium chloride (c) Which substance is the reductant, and which is the oxidant?

Hydrazine (N₂H₄) and dinitrogen tetroxide (N₂O₄) form a self-igniting mixture that has been used as a rocket propellant. The reaction products are N₂ and H₂O. (a) Write a balanced chemical equation for this reaction.

Hydrazine (N₂H₄) and dinitrogen tetroxide (N₂O₄) form a self-igniting mixture that has been used as a rocket propellant. The reaction products are N₂ and H₂O. (c) Which substance serves as the reducing agent and which as the oxidizing agent?

Complete and balance the following half-reactions. In each case, indicate whether the half-reaction is an oxidation or a reduction. (a) Sn²⁺(aq) → Sn⁴⁺(aq) (acidic solution) (b) TiO₂(s) → Ti²⁺(aq) (acidic solution) (c) ClO₃^-(aq) → Cl^-(aq) (acidic solution) (d) N₂(g) → NH₄⁺(aq) (acidic solution)

Complete and balance the following half-reactions. In each case, indicate whether the half-reaction is an oxidation or a reduction. (f) SO32-1aq2 ¡ SO42-1aq2 (basic solution)

Complete and balance the following half-reactions. In each case indicate whether the half-reaction is an oxidation or a reduction. (a) Mo³⁺(aq) → Mo(s) (acidic solution) (b) H₂SO₃(aq) → SO₄^2-(aq) (acidic solution) (c) NO₃^-(aq) → NO(g) (acidic solution) (d) O₂(g) → H₂O(l) (acidic solution)

Complete and balance the following half-reactions. In each case indicate whether the half-reaction is an oxidation or a reduction. (g) Cr(OH)₃(s) → CrO₄^2-(aq) (basic solution)

Complete and balance the following equations, and identify the oxidizing and reducing agents: (a) Cr₂O₇^2-(aq) + I^-(aq) → Cr³⁺(aq) + IO₃^-(aq) (acidic solution) (b) MnO₄^-(aq) + CH₃O(1aq) → Mn²⁺(aq) + HCOOH(aq) (acidic solution) (c) I₂(s) + OCl^-(aq) → IO₃^-(aq) + Cl^-(aq) (acidic solution)

Complete and balance the following equations, and identify the oxidizing and reducing agents: As₂O₃(s) + NO₃^-(aq) → H₃AsO₄(aq) + N₂O₃(aq) (acidic solution)

Complete and balance the following equations, and identify the oxidizing and reducing agents: MnO₄^-(aq) + Br^-(aq) → MnO₂(s) + BrO₃^-(aq) (basic solution)

Complete and balance the following equations, and identify the oxidizing and reducing agents. (Recall that the O atoms in hydrogen peroxide, H₂O₂, have an atypical oxidation state.) (a) NO₂^-(aq) + Cr₂O₇^2-(aq) → Cr³⁺(aq) + NO₃^-(aq) (acidic solution) (b) S(s) + HNO₃(aq) → H₂SO₃(aq) + N₂O(g) (acidic solution) (c) Cr₂O₇^2- (aq) + CH₃OH(aq) → HCOOH(aq) + Cr³⁺(aq) (acidic solution) (d) BrO₃^-(aq) + N₂H₄(g) → Br^-(aq) + N₂(g) (acidic solution)

Complete and balance the following equations, and identify the oxidizing and reducing agents. (Recall that the O atoms in hydrogen peroxide, H2O2, have an atypical oxidation state.) H2O21aq2 + ClO21aq2 ¡ ClO2-1aq2 + O21g2 (basic solution)

Indicate whether each statement is true or false: (c) A salt bridge or permeable barrier is necessary to allow a voltaic cell to operate.

A voltaic cell similar to that shown in Figure 20.5 is constructed. One electrode half-cell consists of a silver strip placed in a solution of AgNO3, and the other has an iron strip placed in a solution of FeCl2. The overall cell reaction is Fe1s2 + 2 Ag+1aq2 ¡ Fe2+1aq2 + 2 Ag1s2 (f) In which directions do the cations and anions migrate through the solution?

(a) What is the definition of the volt?

(b) Do all voltaic cells produce a positive cell potential?