The E ^ values of A . B and C are given. Which element/(s) is/(are) good for coating the surface of iron to prevent corrosion? Given: [ E _ Fe ²⁺ / Fe ^0=-0.44 ~V ; E _ A ²⁺ / A ^0=-2.37 ~V ; E _ B ²⁺ / B ^0=-0.15 ~V ; E _ C ²⁺ / C ^0=+0.34 ~V ]

Step-by-step solution

To prevent the corrosion of iron, the metal used for coating must act as a sacrificial anode. This means the coating metal must have a more negative standard reduction potential than that of iron ( E^ _ Fe²⁺/Fe = -0.44 V ). Comparing the given standard reduction potentials: E^ _ A²⁺/A = -2.37 V E^ _ B²⁺/B = -0.15 V E^ _ C²⁺/C = +0.34 V Since -2.37 V Elements B and C have reduction potentials greater than -0.44 V , meaning they are more noble than iron and would not provide sacrificial protection. Answer: Element A