Chapter 21 Electrochemistry Chemical Change and Electrical Work Chapter 21 Electrochemistry Chemical Change and Electrical Work 1 Which one of the following is not a redox reaction A Al OH 4 aq 4H aq Al3 aq 4H2O l B C6H12O6 s 6O2 g 6CO2 g 6H2O l C Na6FeCl8 s 2Na l 8NaCl s Fe s D 2H2O2 aq 2H2O l O2 g E CO2 g H2 g CO g H2O g Ans A 2 Consider the reaction CuO s H2 g Cu s H2O l In this reaction which substances are the oxidant and reductant respectively A CuO and H2 D H2O and H2 B H2 and CuO E None of these choices is correct C CuO and Cu Ans A 3 Consider the following balanced redox reaction Mn2 aq S2O82 aq 2H2O l MnO2 s 4H aq 2SO42 aq Which of the following statements is true A Mn2 aq is the oxidizing agent and is reduced B Mn2 aq is the oxidizing agent and is oxidized C Mn2 aq is the reducing agent and is oxidized D Mn2 aq is the reducing agent and is reduced E Manganese does not change its oxidation number in this reaction Ans C 4 Consider the following balanced redox reaction 3CuO s 2NH3 aq N2 g 3H2O l 3Cu s Which of the following statements is true A CuO s is the oxidizing agent and copper is reduced B CuO s is the oxidizing agent and copper is oxidized C CuO s is the reducing agent and copper is oxidized D CuO s is the reducing agent and copper is reduced E CuO s is the oxidizing agent and N2 g is the reducing agent Ans A 5 When the following redox equation is balanced with smallest whole number coefficients the coefficient for nitrogen dioxide will be I2 s HNO3 aq HIO3 aq NO2 g H2O l A 1 B 2 C 4 D 10 E None of these choices is correct Ans D Page 292 2013 by McGraw Hill Education This is proprietary material solely for authorized instructor use Not authorized for sale or distribution in any manner This document may not be copied scanned duplicated forwarded distributed or posted on a website in whole or part Chapter 21 Electrochemistry Chemical Change and Electrical Work 6 When the following redox equation is balanced with smallest whole number coefficients the coefficient for the hydrogen sulfate ion will be Al s HSO4 aq OH aq Al2O3 s S2 aq H2O l A 1 B 3 C 4 D 8 E None of these choices is correct Ans B 7 When the following redox equation is balanced with smallest whole number coefficients the coefficient for zinc will be Zn s ReO4 aq Re s Zn2 aq acidic solution A 2 B 7 C 8 D 16 E None of these choices is correct Ans B 8 When the following redox equation is balanced with smallest whole number coefficients the coefficient for the iodide ion will be I aq NO3 aq NO g I2 s acidic solution A 2 B 3 C 6 D 8 E None of these choices is correct Ans C 9 When the following redox equation is balanced with smallest whole number coefficients the coefficient for Sn OH 3 will be Bi OH 3 s Sn OH 3 aq Sn OH 62 aq Bi s basic solution A 1 B 2 C 3 D 6 E None of these choices is correct Ans C 10 Consider the following redox equation Mn OH 2 s MnO4 aq MnO42 aq basic solution When the equation is balanced with smallest whole number coefficients what is the coefficient for OH aq and on which side of the equation is OH aq present A 4 reactant side D 6 product side B 4 product side E None of these choices is correct C 6 reactant side Ans C 11 Which of the following statements about voltaic and electrolytic cells is correct A The electrons in the external wire flow from cathode to anode in both types of cell B Oxidation occurs at the cathode only in a voltaic cell C The free energy change G is negative for an electrolytic cell D The cathode is labeled as positive in a voltaic cell but negative in an electrolytic cell E Reduction occurs at the anode in an electrolytic cell Ans D Page 293 2013 by McGraw Hill Education This is proprietary material solely for authorized instructor use Not authorized for sale or distribution in any manner This document may not be copied scanned duplicated forwarded distributed or posted on a website in whole or part Chapter 21 Electrochemistry Chemical Change and Electrical Work 12 Which of the following statements about voltaic and electrolytic cells is correct A The anode will definitely gain weight in a voltaic cell B Oxidation occurs at the cathode of both cells C The free energy change G is negative for the voltaic cell D The electrons in the external wire flow from cathode to anode in an electrolytic cell E None of these statements is correct Ans C 13 Which one of the following pairs of substances could be used to construct a single redox electrode i e they have an element in common but in different oxidation states A HCl and ClD Fe3 and Fe2O3 B H and OHE MnO2 and Mn2 C H2O and H Ans E 14 Which one of the following statements about electrochemical cells is correct A In a salt bridge current is carried by cations moving toward the anode and anions toward the cathode B In the external wire electrons travel from cathode to anode C The anode of a voltaic cell is labeled minus D Oxidation occurs at the cathode in an electrolytic cell E None of these statements is correct Ans C 15 Which of the following solids is commonly used as an inactive electrode in electrochemical cells A zinc B graphite C copper D iron E sodium Ans B 16 Which component of the following cell notation is the anode P Q R S A P B Q C R D S E One of the symbols is the anode Ans A 17 A voltaic cell is prepared using copper and silver Its cell notation is shown below Cu s Cu2 aq Ag aq Ag s Which of the following processes occurs at the cathode A Cu s Cu2 aq 2eB Cu2 aq 2e Cu s C Ag s Ag aq eD Ag aq e Ag s E Cu s 2Ag aq Cu2 aq 2Ag s Ans D Page 294 2013 by McGraw Hill Education This is proprietary material solely for authorized instructor use Not authorized for sale or distribution in any manner This document may not be copied scanned duplicated forwarded distributed or posted on a website in whole or part Chapter 21 Electrochemistry Chemical Change and Electrical Work 18 A voltaic cell prepared using aluminum and nickel has the following cell notation Al s Al3 aq Ni2 aq Ni s Which of the following reactions occurs at the anode A Al s Al3 aq 3eD Ni2 aq 2e Ni s B …