Question

When connected to a hydrogen electrode, an electrode with a negative standard reduction potential will carry out

reduction


oxidation


both oxidation and reduction


neither oxidation or reduction

Answer 1

Explanation:

In this standard hydrogen electrode, the hydrogen electrode is acting as anode. Therefore, in hydrogen or anode half cell oxidation will take place. Reaction occurring at anode,

H

2

⇌2H

+

+2e

−

, E

0

=0

At cathode reduction should take place. Metals lying below hydrogen in the reactivity series have positive value of reduction potential and are poor reducing agents and good oxidising agents. Thus, they reduce themselves. Among the given metals Cu and Hg lie below H and have positive reduction potentials. Hence, they can act as cathode.

Reaction occurring at cathode,

Cu

+2

+2e

−

⇌Cu(s); E

0

=+0.34V

Hg

+2

+2e

−

⇌Hg(s); E

0

=+0.885V