Question : 71.              The following reaction occurs in a lead storage battery: PbO2(s) : 1335551

71.              The following reaction occurs in a lead storage battery:

PbO2(s) + Pb(s) + H2SO4(aq) 2PbSO4(s) + 2H2O(l)

What happens to the sulfuric acid in a lead storage battery when the battery is being discharged?

A)Sulfate ions are consumed and their concentration decreases.

B)Protons are released so the pH drops.

C)The solution gets increasingly more viscous due to an increase in sulfuric acid concentration.

D)Its concentration increases.

E)All of these are correct.

72.              The following reaction occurs in a lead storage battery:

PbO2(s) + Pb(s) + H2SO4(aq) 2PbSO4(s) + 2H2O(l)

Which statement is true?

A)The concentration of H2SO4 increases as the battery discharges.

B)Pb is formed at the anode during charging.

C)PbO2 is formed at the anode during charging.

D)The mass of Pb decreases during charging.

E)The mass of PbSO4 remains constant during charging and discharging.

73.              Consider the skeletal equation:

Sn2+(aq) + Fe3+(aq) ? Sn4+(aq) + Fe2+(aq)

When balanced, the equation will be:

A)Sn2+(aq) + Fe3+(aq) ? Sn4+(aq) + Fe2+(aq)

B)2Sn2+(aq) + Fe3+(aq) ? Sn4+(aq) + Fe2+(aq)

C)2Sn2+(aq) + Fe3+(aq) ? 2Sn4+(aq) + Fe2+(aq)

D)Sn2+(aq) + 2Fe3+(aq) ? Sn4+(aq) + 2Fe2+(aq)

E)4Sn2+(aq) + Fe3+(aq) ? 2Sn4+(aq) + Fe2+(aq)

74.              A voltaic cell is prepared in which copper metal is oxidized to Cu(II), and silver ion is reduced to silver metal.  Which of the following represents the correctly balanced equation for this reaction?

A)Cu(s) + Ag+(aq) ? Cu2+(aq) + Ag(s)

B)2Cu(s) + Ag+(aq) ? 2Cu2+(aq) + Ag(s)

C)Cu(s) + 2Ag+(aq) ? Cu2+(aq) + 2Ag(s)

D)3Cu(s) + 2Ag+(aq) ? 3Cu2+(aq) + 2Ag(s)

E)2Cu(s) + 3Ag+(aq) ? 2Cu2+(aq) + 3Ag(s)

75.              A voltaic cell is prepared in which copper metal is oxidized to Cu(II), and silver ion is reduced to silver metal.  Which of the following represents the equation for the reaction that occurs at the anode?

A)Cu(s) – 2e– ? Cu2+(aq)D)Ag+(aq) + e– ?  Ag(s)

B)Cu(s) ? Cu2+(aq) + 2e–E)Ag(s) ? Ag+(aq) + e–

C)2Cu(s) ? 2Cu2+(aq) + e–

76.              A voltaic cell is prepared in which aluminum metal is oxidized to Al3+, and nickel(II) is reduced to nickel metal.  Which of the following represents the correctly balanced equation for this reaction?

A)Al(s) + Ni2+(aq) ? Al3+(aq) + Ni(s)

B)Al(s) + 2Ni2+(aq) ? Al3+(aq) + 2Ni(s)

C)2Al(s) + 3Ni2+(aq) ? 2Al3+(aq) + 3Ni(s)

D)Al3+(aq) + 2Ni(s) ? Al(s) + 2Ni2+(aq)

E)2Al3+(aq) + 3Ni(s) ? 2Al(s) + 3Ni2+(aq)

77.              If the following equation is properly balanced with the smallest whole-number coefficients, what is the coefficient of Bi3+?

Mn2+(aq) + BiO3–(aq) ? MnO4–(aq) + Bi3+(aq)

A)  1    B)  2    C)  3    D)  4    E)  5

78.              The following reaction occurs in acid solution.  When the equation is properly balanced with the smallest whole-number coefficients, what is the coefficient of MnO4–?

MnO4–(aq) + I–(aq) ? Mn2+(aq) + I2(aq)

A)  1    B)  2    C)  3    D)  4    E)  5

79.              A voltaic cell is prepared in which aluminum metal is oxidized to Al3+, and nickel(II) is reduced to nickel metal.  Which of the following represents the equation for the reaction that occurs at the anode?

A)Al(s) ? Al3+(aq) + 3e–D)Al3+(aq) + 3e– ? Al(s)

B)Ni2+(aq) + 2e– ? Ni(s)E)2Al3+(aq) + 3e– ? 2Al(s)

C)Ni(s) ? Ni2+(aq) + 2e–

80.              Consider the half-reaction Cr3+(aq) ? Cr2O72?(aq).  When the equation is balanced in acid solution, the coefficient for water will be__________, and the number of electrons transferred will be __________.

A)  3, 3    B)  6, 6    C)  7, 6    D)  5, 4    E)  3, 6