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) + Cr2O72-(aq) → Cr3+(aq) + NO3-(aq) (acidic solution) (b) S(s) + HNO3(aq) → H2SO3(aq) + N2O(g) (acidic solution) (c) Cr2O72- (aq) + CH3OH(aq) → HCOOH(aq) + Cr3+(aq) (acidic solution) (d) BrO3-(aq) + N2H4(g) → Br-(aq) + N2(g) (acidic solution)
Indicate whether each statement is true or false: (a) The cathode is the electrode at which oxidation takes place. (b) A galvanic cell is another name for a voltaic cell. (c) Electrons flow spontaneously from anode to cathode in a voltaic cell.

Key Concepts
Electrochemical Cells
Galvanic (Voltaic) Cells
Oxidation and Reduction
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. S(s) + HNO3(aq) → H2SO3(aq) + N2O(g) (acidic solution)
b. BrO3-(aq) + N2H4(g) → Br-(aq) + N2(g) (acidic solution)
c. H2O2(aq) + ClO2(aq) → ClO20(aq) _ O2(g) (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.) 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?