Question

$E_{C{u}^{2+}|Cu}^0=+034V$

$E_{Z{n}^{2+}|Zn}^0=-0.76V$

Identify the incorrect statement from the below for the above cell :
(JEE MAIN 2019)

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

Answer 1

The correct option is B 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 .