Question

Question number 134 answer

Answer 1

The most important point to be noted is that, "Standard reduction potential is the potential of a substance to get reduced"

In simpler words, more positive SRP value indicates a greater tendency to get reduced and negative SRP value indicates a greater tendency to get oxidised.

Given,

Zn²⁺ + 2e⁻  → Zn,  SRP = -0.762

Cr³⁺ + 3e⁻ →  Cr,  SRP = -0.740

2H⁺ + 2e⁻  → H₂,  SRP = 0.00

Fe³⁺ + 3e⁻  → Fe, SRP = 0.762

Of these, the one with the most negative value of SRP will have the least tendency to get reduced or the most tendency to get oxidised.

NOTE: Anode is where oxidation takes place, so it is a place where substances get oxidised. Similarly, reduction takes place at Cathode.

As Zn has the most negative SRP value of them all, it cannot get reduced and only gets oxidised when treated with the other reaction cells above, thus acting as the "Anode"

Hope it helps!!