Question

\(E^{0}_{Cu^{2+}|{Cu}}= +034~V\)

\(E^{0}_{Zn^{2+}|{Zn}}= -0.76~V\)

Identify the incorrect statement from the below for the above cell :
Curod +ve M Cuso, soln

• A. If $E_{ext}<1.1V$ , Zn dissolves at anode and Cu deposits at cathode
• B. If $E_{ext}>1.1V$ , $e^{-}$ flow from Cu top Zn
• C. If $E_{ext}>1.1V$ , Zn dissolves at Zn electrode and Cu deposits at Cu electrode
• D. If $E_{ext}=1.1V$, no flow of $e^{-}$ or current occurs

Answer 1

The correct option is C If $E_{ext}>1.1V$ , Zn dissolves at Zn electrode and Cu deposits at Cu electrode

$E_{cell}^0=E_{C{u}^{2+}|Cu}^0-E_{Z{n}^{2+}|Zn}^0=1.1V$

so If $E_{ext}=1.1V$, no electron will flow

At $E_{ext}>1.1V$, cell act as electrolytic cell and electron will flow from Cu to Zn .

At $E_{ext}<1.1V$, cell act as electrochemical cell so Zn dissolve and Cu deposit .