Question -
Answer -
The reduction potentials of zincand iron are lower than that of copper. In hydrometallurgy, zinc and iron canbe used to displace copper from their solution.
But to displace zinc, morereactive metals i.e., metals having lower reduction potentials than zinc suchas Mg, Ca, K, etc. are required. But all these metals react with water with theevolution of H2┬аgas.
As a result, these metals cannotbe used in hydrometallurgy to extract zinc.
Hence,copper can be extracted by hydrometallurgy but not zinc.