Passage III
An electrochemical cell (Figure 1) is constructed with an anode, a strip of zinc (Zn) placed in a solution of zinc ions (Zn2+), and a cathode, a strip of copper (Cu) or silver (Ag) placed in a solution of copper ions (Cu2+) or silver ions (Ag1+) , respectively. The solutions are connected by a salt bridge (a tube filled with a solution containing nitrate ions). The anode and cathode are connected to a voltmeter. Tables 1 and 2 show how the mass (g) of the anode or cathode, concentrations (M) of the ionic solutions, and temperature (°C), affect the voltage difference(V) between Zn and either Cu or Ag.
14. Which of the following pairs of Zn-Cu cells supports the conclusion that increasing the Zn2+ concentration decreases the voltage difference?
Your Answer is
Correct Answer is J
Explanation
The concentration of Zn2+ in Cell 5 is higher. It can be seen from table 1 that the other conditions of Cell 3 and Cell 5 are the same, only the concentration of Zn2+< /sup>This is different, so by comparison, it is found that the voltage difference of Cell 5 is smaller