Question

Which of the following will act as cathode when connected to standard hydrogen electrode which has $E^{o}$ value given as zero?

(i) $Zn^{2 +}/Zn,E^{o} = - 0.76V$

(ii) $Cu^{2 +}/Cu,E^{o} = + 0.34V$

(iii) $Al^{3 +}/Al,E^{o} = - 1.66V$

(iv) $Hg^{2 +}Hg,E^{o} = + 0.885V$

• A. (i) and (ii)
• B. (ii) and (iv)
• C. (i) and (iii)
• D. (i), (ii), (iii) and (iv)

Answer 1

Answer: (B)

(ii) and (iv)

Answer 2

: When the value of standard reduction potential is positive, the electrode undergoes reduction and acts as cathode.